在矩阵上写出字母 Y 所需的最少操作次数

Leetcode题目链接

描述

详见中文题目链接。

解答

class Solution {
public:
    int minimumOperationsToWriteY(vector<vector<int>>& grid) {
        array<int, 3> countY{0}, countOut{0};

        int m = grid.size();
        for (int i = 0; i < m; i++) {
            for (int j = 0; j < m; j++) {
                if ((i == j && i <= m / 2) 
                || (i + j == m - 1 && i <= m / 2) 
                || (i > m / 2 && j == m / 2)) {
                    countY[grid[i][j]]++;
                } else countOut[grid[i][j]]++;
            }
        }

        int maxNotChange = 0;
        for (int i = 0; i < 3; i++) {
            for (int j = 0; j < 3; j++) {
                if (i != j)
                    maxNotChange = max(maxNotChange, countY[i] + countOut[j]);
            }
        }

        return m * m - maxNotChange;
    }
};