leetcode778. 水位上升的泳池中游泳

https://leetcode-cn.com/problems/swim-in-rising-water/submissions/
这道题本来不打算写博客的，之所以写，是因为可能运气比较好，执行时间超过100%，来炫耀一下

这道题的思路简直就是挖地雷

代码

boolean su = false;

public int swimInWater(int[][] grid) {
    int N = grid.length;
    int ans = Math.max(grid[0][0], grid[N - 1][N - 1]);
    while (true) {
        //从(0,0)开始挖地雷，数字变成ans+1，防止重复
        change(0, 0, N, grid, ans + 1);
        if (grid[N - 1][N - 1] == ans + 1) {
            return ans;
        }
        ans++;
    }
}

private void change(int x, int y, int N, int[][] grid, int key) {
    if (grid[x][y] >= key) {
        return;
    }
    grid[x][y] = key;
    if (x > 0) {
        change(x - 1, y, N, grid, key);
    }
    if (y > 0) {
        change(x, y - 1, N, grid, key);
    }
    if (x < N - 1) {
        change(x + 1, y, N, grid, key);
    }
    if (y < N - 1) {
        change(x, y + 1, N, grid, key);
    }
}