3127. Make a Square with the Same Color 

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class Solution {
    public boolean canMakeSquare(char[][] grid) {
        // 思路：以每个节点为左上角根节点进行扫描，统计出 2 * 2 正方形区域中的黑色格子、白色格子的个数
        // 黑色 + 白色的所有组合方式：0 + 4, 1 + 3, 2 + 2, 3 + 1, 4 + 0, 可以观察出黑色或白色为 2 时无法满足题意

        for (int i = 0; i < grid.length - 1; i++) {
            for (int j = 0; j < grid[i].length - 1; j++) {
                int whiteCount = whiteCount(grid[i][j]) + whiteCount(grid[i][j + 1]) + whiteCount(grid[i + 1][j]) + whiteCount(grid[i + 1][j + 1]);
                if (whiteCount != 2) {
                    return true;
                }
            }
        }

        return false;
    }

    private int whiteCount(char c) {
        return c == 'W' ? 1 : 0;
    }
}

Reference

3127. Make a Square with the Same Color