文章作者：Tyan
博客：noahsnail.com | CSDN | 简书
1. Description
Valid Sudoku
Valid Sudoku
2. Solution
class Solution {
public:
bool isValidSudoku(vector<vector<char>>& board) {
return validate(board);
}
private:
bool validate(vector<vector<char>>& board) {
int n = board.size();
vector<vector<unordered_map<char, char>>> subboxes(3, vector<unordered_map<char, char>>(3));
for(int i = 0; i < n; i++) {
unordered_map<char, char> row;
unordered_map<char, char> column;
for(int j = 0; j < n; j++) {
if(board[i][j] != '.') {
if(row.find(board[i][j]) != row.end()) {
return false;
}
else {
row[board[i][j]] = board[i][j];
}
if(subboxes[i / 3][j / 3].find(board[i][j]) != row.end()) {
return false;
}
else {
subboxes[i / 3][j / 3][board[i][j]] = board[i][j];
}
}
if(board[j][i] != '.') {
if(column.find(board[j][i]) != column.end()) {
return false;
}
else {
column[board[j][i]] = board[j][i];
}
}
}
}
return true;
}
};
