【LeetCode】036. Valid Sudoku

题目：

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.

题解：

Solution 1

class Solution {

public:

    bool isValidSudoku(vector<vector<char>>& board) {

        const int n = ;

        for(int i = ; i < n; ++i){

            bool used[n] = {false};

            for(int j = ; j < n; ++j){

                if(isused(board[i][j], used))

                    return false;

            }

        }

        for(int i = ; i < n; ++i){

            bool used[n] = {false};

            for(int j = ; j < n; ++j){

                if(isused(board[j][i], used))

                    return false;

            }

        }

        for(int r = ; r < ; ++r){

            for(int c = ; c < ; ++c){

                bool used[n] = {false};

                for(int i = r * ; i < r *  + ; ++i){

                    for(int j = c * ; j < c *  + ; ++j){

                        if(isused(board[i][j], used))

                           return false;

                    }

                }

            }

        }

        return true;

    }

    bool isused(char val, bool used[]){

        if(val == '.')

            return false;

        if(used[val - ''])

            return true;

        used[val - ''] = true;

        return false;

    }

};

Solution 2

class Solution {

public:

    bool isValidSudoku(vector<vector<char>>& board) {

        const int n = ;

        vector<vector<bool>> rowboard(n, vector<bool>(n, false));

        vector<vector<bool>> colboard(n, vector<bool>(n, false));

        vector<vector<bool>> celboard(n, vector<bool>(n, false));

        for(int i = ; i < n; ++i){

            for(int j = ; j < n; ++j){

                if(board[i][j] == '.') continue;

                int ch = board[i][j] - '';

                if(rowboard[i][ch] || colboard[ch][j] || celboard[ * (i / ) + j / ][ch])

                    return false;

                rowboard[i][ch] = true;

                colboard[ch][j] = true;

                celboard[ * (i / ) + j / ][ch] = true;

            }

        }

        return true;

    }

};

巴特西

【LeetCode】036. Valid Sudoku

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