leetcode 36. Valid Sudoku

啊，我还以为求数独呢，原来是求当前的是否符合数独的规范。。

那就横、竖、小九宫格分别判断是否有相同的呗。

class Solution {
public:
bool isValidSudoku(vector<vector<char>>& board) {
unordered_map<char, bool> row, col, all;
for (int i = 0; i < 9; ++i) {
col.clear();
for (int j = 0; j < 9; ++j) {
char ch = board[j][i];
if (ch == '.')
continue;
if (col.find(ch) != col.end())
return false;
else
col.insert({ch, true});
}
}

for (int i = 0; i < 9; ++i) {
row.clear();
for (int j = 0; j < 9; ++j) {
char ch = board[i][j];
if (ch == '.')
continue;
if (row.find(ch) != row.end())
return false;
else
row.insert({ch, true});
}
}

for (int i = 0; i < 8; i += 3) {
for (int j = 0; j < 8; j += 3) {
all.clear();
for (int k = 0; k < 3; ++k) {
for (int l = 0; l < 3; ++l) {

char ch = board[i + k][j + l];
if (ch == '.')
continue;
if (all.find(ch) != all.end())
return false;
else
all.insert({ch, true});
}
}
}
}
return true;
}
};