int main(int argc, char* argv[]) {
while (true) {
SudokuBoard* board = readBoard(stdin);
if (board == NULL) {
break;
}
if (!isValidBoard(board)) {
printf("Invalid board.\n");
freeSudokuBoard(board);
continue;
}
SudokuBoard* solved = solveBoard(board);
if (solved == NULL) {
printf("No solution found.\n");
freeSudokuBoard(board);
continue;
}
drawSudokuBoardSimple(solved);
if (solved != board) {
freeSudokuBoard(solved);
}
freeSudokuBoard(board);
}
return 0;
}
// 检查从当前局面开始是否能够得到最终合法有效的解
bool solveSudoku(vector<vector<char> >& board) {
// 如果没有找到空白的格子，说明已经填满了，成功返回
pair<int, int> pos = findFirstEmpty(board);
if (pos.first == -1 && pos.second == -1)
return true;
// 否则依次尝试往当前格子中填入数字 1-9，并判断能否得到可行的解
for (int i = 1; i <= 9; ++i) {
board[pos.first][pos.second] = i + '0';
if (isValidBoard(board, pos) && solveSudoku(board))
return true;
// 恢复原样
board[pos.first][pos.second] = '.';
}
return false;
}
/**
* Returns whether you have a valid, complete board
*/
bool isCompleteBoard(SudokuBoard* board) {
if (board == NULL) {
return false;
}
// make sure everything is full
for (int i = 0; i < BOARD_SIZE; i++) {
for (int j = 0; j < BOARD_SIZE; j++) {
Tile tile = board->tiles[i][j];
if (tile.value == 0) {
return false;
}
}
}
return isValidBoard(board);
}
