输入: mat = [[1,4],[3,2]]
输出: [0,1]
解释: 3和4都是顶峰元素，所以[1,0]和[0,1]都是可接受的答案。

输入: mat = [[10,20,15],[21,30,14],[7,16,32]]
输出: [1,1]
解释: 30和32都是顶峰元素，所以[1,1]和[2,2]都是可接受的答案。
 
提示：
m == mat.length
n == mat[i].length
1 <= m, n <= 500
1 <= mat[i][j] <= 10^5
任意两个相邻元素均不相等.

class Solution {
public:
    vector<int> findPeakGrid(vector<vector<int>>& mat) {
        int m = mat.size(), n = mat[0].size();
        int l = 0, r = m-1, mid;
        int u, v, w, idx;
        vector<int> res;
        while(l <= r)
        {
            mid = (l+r)>>1;
            res = getmax(mat, mid, m, n);
            u = res[0], idx = res[1];
            res =  getmax(mat, mid-1, m, n);
            v = res[0];
            res =  getmax(mat, mid+1, m, n);
            w = res[0];
            if(u>=v && u>=w) return {mid, idx};
            else if(v >= u)
                r = mid-1;
            else
                l = mid+1;
        }
        return {-1, -1};
    }
    vector<int> getmax(vector<vector<int>>& mat, int r, int m, int n)
    {
        if(r < 0 || r >= m) return {-1, -1};
        int maxv = -1, idx = -1;
        for(int i = 0; i < n; ++i)
        {
            if(maxv < mat[r][i])
            {
                idx = i;
                maxv = mat[r][i];
            }
        }
        return {maxv, idx};
    }
};