[英]Sudoku Solver code gives unexpected result
问题链接: https://leetcode.com/problems/valid-sudoku/description/
下面是我的数独求解器代码。 如果数独是可解的,我应该返回 true,否则返回 false。
class Solution {
public:
bool solveSudoku(vector<vector<char>> &board, int row, int col) {
// If the position is now at the end of the 9*9 grid
if(row == 8 and col == 9) return true;
// if column has reached upper bound
if(col==9) {
row++;
col=0;
}
// For characters other than dot move to the next position
if(board[row][col]!='.') return solveSudoku(board,row,col+1);
for(int i=1; i<=9; i++) {
char num='0'+i;
if(isValid(board, row, col, num)) {
board[row][col]=num;
if(solveSudoku(board,row,col+1)) return true;
}
board[row][col]='.';
}
return false;
}
bool isValid(vector<vector<char>> &board, int row, int col, char num) {
int i,j;
/* Checking if its duplicated on the same row */
for(i=0; i<9; i++) {
if(i!=col && board[row][i] == num) {
return false;
}
}
/* Checking if its duplicated on the same col */
for(i=0; i<9; i++) {
if(i!=row && board[i][col] == num) {
return false;
}
}
/* Checking if its duplicated inside the 3*3 grid */
int rowOffset=row-(row%3);
int colOffset=col-(col%3);
for(i=0; i<3;i++) {
for(j=0;j<3;j++) {
if((rowOffset+i)!=row && (colOffset+j)!=col && board[rowOffset+i][colOffset+j] == num) {
return false;
}
}
}
return true;
}
bool isValidSudoku(vector<vector<char>>& board) {
if(solveSudoku(board, 0, 0)) return true;
return false;
}
};
对于以下测试输入
[[".","8","7", "6","5","4", "3","2","1"],
["2",".",".", ".",".",".", ".",".","."],
["3",".",".", ".",".",".", ".",".","."],
["4",".",".", ".",".",".", ".",".","."],
["5",".",".", ".",".",".", ".",".","."],
["6",".",".", ".",".",".", ".",".","."],
["7",".",".", ".",".",".", ".",".","."],
["8",".",".", ".",".",".", ".",".","."],
["9",".",".", ".",".",".", ".",".","."]]
注意:这是一个 leetcode 问题
它返回错误,我认为这是正确的,但预期的答案是正确的。 这怎么可能是一个错误的答案。 谁能解释一下。
提前致谢
你误解了任务。
确定 9 x 9 数独板是否有效。 只有填充的单元格需要根据以下规则进行验证:
填充的单元格不违反数独规则。
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