578 lines
15 KiB
C
578 lines
15 KiB
C
/****************************************************************************
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* apps/system/sudoku/sudoku.c
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*
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* Copyright (C) 2014 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <gnutt@nuttx.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name NuttX nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <stdint.h>
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#include <stdio.h>
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#include <string.h>
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#include <apps/readline.h>
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/****************************************************************************
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* Pre-processor Definitions
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****************************************************************************/
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#define NHISTORY 16
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/****************************************************************************
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* Private Types
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****************************************************************************/
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struct sudoku_s
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{
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uint16_t canbe;
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uint16_t is;
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};
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typedef struct sudoku_s sudoku_t[81];
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/****************************************************************************
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* Private Data
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****************************************************************************/
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static sudoku_t history[NHISTORY];
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static sudoku_t working;
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static int first;
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static int last;
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static int current;
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static const char *r1[8] =
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{" ", "1 ", " 2 ", "12 ", " 3", "1 3", " 23", "123" };
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static const char *r2[8] =
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{" ", "4 ", " 5 ", "45 ", " 6", "4 6", " 56", "456" };
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static const char *r3[8] =
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{" ", "7 ", " 8 ", "78 ", " 9", "7 9", " 89", "789" };
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static char line[256];
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static int nis = 0;
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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static inline void init_array(void)
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{
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int i;
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first = 0;
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last = 0;
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current = 0;
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for (i = 0; i < 81; i++)
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{
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working[i].canbe = 0x1ff;
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working[i].is = 0x000;
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}
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}
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static inline void push(void)
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{
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int next = current + 1;
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if (next >= NHISTORY) next = 0;
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if (current == last)
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{
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last = next;
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}
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if (first == next)
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{
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if (++first >= NHISTORY) first = 0;
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}
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memcpy (history[current], working, sizeof(sudoku_t));
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current = next;
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}
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static inline void undo(void)
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{
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if (current == first)
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{
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printf("Cannot undo\n");
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}
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else
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{
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if (--current < 0) current = NHISTORY-1;
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memcpy (working, history[current], sizeof(sudoku_t));
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}
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}
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static inline void redo(void)
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{
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if (current == last)
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{
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printf("Cannot redo\n");
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}
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else
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{
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if (++current >= NHISTORY) current = 0;
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memcpy(working, history[current], sizeof(sudoku_t));
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}
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}
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static inline void show_row(int row)
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{
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printf(" |%3s|%3s|%3s| |%3s|%3s|%3s| |%3s|%3s|%3s|\n",
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r1[working[9*row + 0].canbe & 0x007],
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r1[working[9*row + 1].canbe & 0x007],
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r1[working[9*row + 2].canbe & 0x007],
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r1[working[9*row + 3].canbe & 0x007],
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r1[working[9*row + 4].canbe & 0x007],
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r1[working[9*row + 5].canbe & 0x007],
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r1[working[9*row + 6].canbe & 0x007],
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r1[working[9*row + 7].canbe & 0x007],
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r1[working[9*row + 8].canbe & 0x007]);
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printf(" %2d |%3s|%3s|%3s| |%3s|%3s|%3s| |%3s|%3s|%3s|\n", row + 1,
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r2[(working[9*row + 0].canbe >> 3) & 0x007],
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r2[(working[9*row + 1].canbe >> 3) & 0x007],
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r2[(working[9*row + 2].canbe >> 3) & 0x007],
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r2[(working[9*row + 3].canbe >> 3) & 0x007],
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r2[(working[9*row + 4].canbe >> 3) & 0x007],
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r2[(working[9*row + 5].canbe >> 3) & 0x007],
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r2[(working[9*row + 6].canbe >> 3) & 0x007],
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r2[(working[9*row + 7].canbe >> 3) & 0x007],
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r2[(working[9*row + 8].canbe >> 3) & 0x007]);
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printf(" |%3s|%3s|%3s| |%3s|%3s|%3s| |%3s|%3s|%3s|\n",
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r3[(working[9*row + 0].canbe >> 6) & 0x007],
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r3[(working[9*row + 1].canbe >> 6) & 0x007],
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r3[(working[9*row + 2].canbe >> 6) & 0x007],
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r3[(working[9*row + 3].canbe >> 6) & 0x007],
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r3[(working[9*row + 4].canbe >> 6) & 0x007],
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r3[(working[9*row + 5].canbe >> 6) & 0x007],
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r3[(working[9*row + 6].canbe >> 6) & 0x007],
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r3[(working[9*row + 7].canbe >> 6) & 0x007],
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r3[(working[9*row + 8].canbe >> 6) & 0x007]);
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}
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static inline void show_array(void)
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{
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int row;
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int i;
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printf(" +===+===+===+ +===+===+===+ +===+===+===+\n");
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printf(" | 1 | 2 | 3 | | 4 | 5 | 6 | | 7 | 8 | 9 |\n");
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printf(" +===+===+===+ +===+===+===+ +===+===+===+\n");
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row = 0;
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for (i = 0; i < 3; i++)
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{
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show_row(row++);
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printf(" +---+---+---+ +---+---+---+ +---+---+---+\n");
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show_row(row++);
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printf(" +---+---+---+ +---+---+---+ +---+---+---+\n");
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show_row(row++);
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printf(" +===+===+===+ +===+===+===+ +===+===+===+\n");
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}
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}
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static inline int is_unique(unsigned int val)
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{
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switch (val)
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{
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case 0x001:
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case 0x002:
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case 0x004:
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case 0x008:
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case 0x010:
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case 0x020:
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case 0x040:
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case 0x080:
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case 0x100:
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return 1;
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default:
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return 0;
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}
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}
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static inline int impossible(void)
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{
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int nchanges = 0;
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unsigned int val;
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int row1, col1;
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int row2, col2;
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int i, j;
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int ndx1, ndx2;
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for (row1 = 0; row1 < 9; row1++)
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{
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row2 = row1 / 3;
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for (col1 = 0; col1 < 9; col1++)
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{
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col2 = col1 / 3;
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ndx1 = row1*9 + col1;
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val = working[ndx1].canbe;
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for (i = 0; i < 9; i++)
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{
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ndx2 = i*9 + col1;
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if (ndx1 != ndx2)
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{
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val &= ~working[ndx2].is;
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}
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}
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for (j = 0; j < 9; j++)
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{
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ndx2 = row1*9 + j;
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if (ndx1 != ndx2)
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{
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val &= ~working[ndx2].is;
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}
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}
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for (i = 0; i < 3; i++)
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{
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for (j = 0; j < 3; j++)
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{
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ndx2 = (row2*3 + i)*9 + (col2*3 + j);
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if (ndx1 != ndx2)
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{
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val &= ~working[ndx2].is;
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}
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}
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}
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if (val == 0)
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{
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return -1;
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}
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if (val != working[ndx1].canbe)
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{
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nchanges++;
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working[ndx1].canbe = val;
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if (is_unique(val))
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{
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working[ndx1].is = val;
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}
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}
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}
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}
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return nchanges;
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}
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static inline int unique(void)
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{
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int noccurences[9];
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int lastndx[9];
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int nchanges = 0;
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unsigned int mask;
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unsigned int val;
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int row1, col1;
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int row2, col2;
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int ndx;
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int i;
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for (row1 = 0; row1 < 9; row1++)
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{
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for (i = 0; i < 9; i++)
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{
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noccurences[i] = 0;
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lastndx[i] = -1;
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}
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for (i = 0; i < 9; i++)
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{
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mask = 1 << i;
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for (col1 = 0; col1 < 9; col1++)
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{
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ndx = row1 * 9 + col1;
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if (working[ndx].canbe & mask)
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{
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noccurences[i]++;
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lastndx[i] = ndx;
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}
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}
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for (i = 0; i < 9; i++)
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{
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if (noccurences[i] == 1)
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{
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val = 1 << i;
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ndx = lastndx[i];
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if (working[ndx].is != val)
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{
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working[ndx].is = val;
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working[ndx].canbe = val;
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nchanges++;
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}
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}
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}
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}
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}
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for (col1 = 0; col1 < 9; col1++)
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{
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for (i = 0; i < 9; i++)
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{
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noccurences[i] = 0;
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lastndx[i] = -1;
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}
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for (i = 0; i < 9; i++)
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{
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mask = 1 << i;
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for (row1 = 0; row1 < 9; row1++)
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{
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ndx = row1 * 9 + col1;
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if (working[ndx].canbe & mask)
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{
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noccurences[i]++;
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lastndx[i] = ndx;
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}
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}
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for (i = 0; i < 9; i++)
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{
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if (noccurences[i] == 1)
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{
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val = 1 << i;
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ndx = lastndx[i];
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if (working[ndx].is != val)
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{
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working[ndx].is = val;
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working[ndx].canbe = val;
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nchanges++;
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}
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}
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}
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}
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}
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for (row2 = 0; row2 < 3; row2++)
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{
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for (col2 = 0; col2 < 3; col2++)
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{
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for (i = 0; i < 9; i++)
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{
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noccurences[i] = 0;
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lastndx[i] = -1;
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}
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for (i = 0; i < 9; i++)
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{
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mask = 1 << i;
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for ( row1 = 0; row1 < 3; row1++)
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{
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for ( col1 = 0; col1 < 3; col1++)
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{
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ndx = (row2*3 + row1)*9 + (col2*3 + col1);
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if (working[ndx].canbe & mask)
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{
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noccurences[i]++;
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lastndx[i] = ndx;
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}
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}
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}
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}
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for (i = 0; i < 9; i++)
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{
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if (noccurences[i] == 1)
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{
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val = 1 << i;
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ndx = lastndx[i];
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if (working[ndx].is != val)
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{
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working[ndx].is = val;
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working[ndx].canbe = val;
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nchanges++;
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}
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}
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}
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}
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}
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return nchanges;
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}
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static inline int getcell(int *pndx, int *pval)
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{
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int row, col, ndx;
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unsigned int val;
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int i = 0;
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while ((line[i] == ' ' || line[i] == '\t') && (line[i] != '\0') && (line[i] != '\n')) i++;
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if (line[i] < '1' || line[i] > '9')
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{
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printf("Bad row: %c\n", line[i]);
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return -1;
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}
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row = line[i++] -'0' - 1;
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while ((line[i] == ' ' || line[i] == '\t') && (line[i] != '\0') && (line[i] != '\n')) i++;
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if (line[i] < '1' || line[i] > '9')
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{
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printf("Bad col: %c\n", line[i]);
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return -1;
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}
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col = line[i++] -'0' - 1;
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ndx = row*9 + col;
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while ((line[i] == ' ' || line[i] == '\t') && (line[i] != '\0') && (line[i] != '\n')) i++;
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if (line[i] < '1' || line[i] > '9')
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{
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printf("Bad value: %c\n", line[i]);
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return -1;
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}
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val = 1 << ((line[i] - '0') - 1);
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if (( val & working[ndx].canbe) == 0)
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{
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printf("Impossible value: %c\n", line[i]);
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return -1;
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}
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*pndx = ndx;
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*pval = val;
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return 0;
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}
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static inline int get_command(void)
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{
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printf("%d of 81> ", nis);
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fflush(stdout);
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(void)readline(line, 256, stdin, stdout);
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int i = 0;
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while ((line[i] == ' ' || line[i] == '\t') && (line[i] != '\0') && (line[i] != '\n')) i++;
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return line[i];
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}
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static inline void show_usage(void)
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{
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printf("ABC - Set cell[A,B] to C where A,B, and C are in {1..9}\n");
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printf("U - Undo last cell assignment\n");
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printf("R - Redo last cell assignment\n");
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printf("H|? - Show this message\n");
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printf("Q - Quit\n");
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}
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static inline void count_cells(void)
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{
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int i;
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nis = 0;
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for (i = 0; i < 81; i++) if (working[i].is > 0) nis++;
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}
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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#ifdef CONFIG_BUILD_KERNEL
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int main(int argc, FAR char *argv[])
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#else
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int sudoku_main(int argc, char **argv, char **envp)
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#endif
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{
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int cmd;
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int nchanged;
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int val;
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int ndx;
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init_array();
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for (;;)
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{
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count_cells();
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show_array();
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if (nis == 81)
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{
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printf("GAME OVER: 81 of 81 assigned\n");
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return 0;
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}
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else
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{
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cmd = get_command();
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switch (cmd)
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{
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case 'U':
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case 'u':
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undo();
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break;
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case 'R':
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case 'r':
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redo();
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break;
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case 'H':
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case 'h':
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case '?':
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show_usage();
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break;
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case 'Q':
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case 'q':
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return 0;
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default:
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if (getcell(&ndx, &val) == 0)
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{
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push();
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working[ndx].is = val;
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working[ndx].canbe = val;
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for (;;)
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{
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nchanged = impossible();
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if (nchanged < 0)
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{
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printf("This move is not possible\n");
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undo();
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break;
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}
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else if (nchanged == 0)
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{
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nchanged = unique();
|
|
if (nchanged == 0)
|
|
{
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|