【Leetcode_easy】840. Magic Squares In Grid

problem

840. Magic Squares In Grid

solution:

class Solution {
public:
    int numMagicSquaresInside(vector<vector<int>>& grid) {
        int m = grid.size(), n = grid[0].size();
        int cnt = 0;
        for(int i=1; i<m-1; ++i)
        {
            for(int j=1; j<n-1; ++j)
            {
                if(isvalid(grid, i, j)) cnt++;
            }
        }
        return cnt;
    }
    bool isvalid(vector<vector<int>>& grid, int i, int j) {
        vector<int> cnt(10);
        for(int x=i-1; x<=i+1; x++)//for loop errr...
        {
            for(int y=j-1; y<=j+1; y++)
            {
                int k=grid[x][y];
                if(k>9 || k<0 || cnt[k]==1) return false;
                cnt[k] = 1;
            }
        }
        if(grid[i][j]!=5) return false;
        if(grid[i-1][j-1]+grid[i-1][j]+grid[i-1][j+1] != 15) return false;
        if(grid[i][j-1]+grid[i][j]+grid[i][j+1] != 15) return false;
        if(grid[i+1][j-1]+grid[i+1][j]+grid[i+1][j+1] != 15) return false;
        if(grid[i-1][j-1]+grid[i][j-1]+grid[i+1][j-1] != 15) return false;
        if(grid[i-1][j]+grid[i][j]+grid[i+1][j] != 15) return false;
        if(grid[i-1][j+1]+grid[i][j+1]+grid[i+1][j+1] != 15) return false;
        if(grid[i-1][j-1]+grid[i][j]+grid[i+1][j+1] != 15) return false;
        if(grid[i-1][j+1]+grid[i][j]+grid[i+1][j-1] != 15) return false;
        return true;
    }
};

 

参考

1. Leetcode_easy_840. Magic Squares In Grid;

2. grandyang;

完