标签：style blog http color os io ar for 2014
Determine if a Sudoku is valid, according to: Sudoku Puzzles - The Rules.
The Sudoku board could be partially filled, where empty cells are filled with the character ‘.‘.
A partially filled sudoku which is valid.
Note:
A valid Sudoku board (partially filled) is not necessarily solvable. Only the filled cells need to be validated.
题意：检查一个给定的数独是否是合理的，该数独可能可有些单元是空白的
思路：
检查每一行，第一列，每一个小方块中是否出现重复数字
可用一个大小为 9的数组表示某个数字是否出现过
复杂度：O(n^2)
bool isExist[9];
bool check(const vector<vector<char> >& board, int i, int j){
if(board[i][j] != '.') {
if (isExist[board[i][j] - '1']) return false;
else return isExist[board[i][j] - '1'] = true;
}
return true;
};
bool isValidSudoku(const vector<vector<char> >& board){
//检查行
for(int i = 0; i < 9; ++i){
memset(isExist, false, sizeof(isExist));
for(int j = 0; j < 9; ++j){
if(!check(board, i, j)) return false;
}
}
//检查列
for(int j = 0; j < 9; ++j){
memset(isExist, false, sizeof(isExist));
for(int i = 0; i < 9; ++i){
if(!check(board, i, j)) return false;
}
}
//检查小方块
for(int k = 0; k < 9; ++k){
memset(isExist, false, sizeof(isExist));
for(int i = 0; i < 3; ++i){
for(int j = 0; j < 3; ++j){
int ii = k % 3 * 3 + i;
int jj = k / 3 * 3 + j;
if(!check(board, ii, jj)) return false;
}
}
}
return true;
}
标签：style blog http color os io ar for 2014
原文地址：http://blog.csdn.net/zhengsenlie/article/details/39119275
