Valid Sudoku 分类： Leetcode（线性表） 2015-02-04 22:05 63人阅读 评论(0) 收藏

Valid Sudoku

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.

 

很简单的思路，遍历。九行九列元素1-9，九个小九宫格元素1-9

class Solution {
public:
    bool isValidSudoku(vector<vector<char> > &board) {
        bool used[9];
        int i,j,r,c;
        
        for(i = 0; i < 9; i++){
            fill(used, used + 9, false);
            
            for(j = 0; j < 9; ++j ){
                if(!check(board[i][j], used))
                return false;
            }
            
            fill(used, used + 9, false);
            
            for(j = 0; j < 9; ++j){
                if(!check(board[j][i], used))
                return false;
            }
            
            for (r = 0; r < 3; ++r){
                for(c = 0; c < 3; ++c){
                    fill(used, used + 9, false);
                    
                    for(int i = r*3; i < r*3 + 3; ++i)
                        for(int j = c*3; j < c*3 + 3; ++j)
                            if(!check(board[i][j], used))
                            return false;
                }
            }
        }
            return true;
        }
    private:
      
        bool check(char ch, bool used[9]){
            if(ch == '.') return true;
            
            if(used[ch - '1']) return false;
            
            return used[ch - '1'] = true;
        }
    
};

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