[LeetCode] Search a 2D Matrix

class Solution {public:    bool searchMatrix(vector<vector<int>>& matrix, int target) {        int m = matrix.size();        int n = matrix[0].size();        int len = m * n;        int l = 0;        int r = len - 1;        int mid;        while(l < r - 1){            mid = l + (r - l) / 2;            int row = mid / n;            int col = mid % n;            if(target < matrix[row][col])   r = mid - 1;            else if(target > matrix[row][col])  l = mid + 1;            else    return true;        }        if(matrix[r / n][r % n] == target)  return true;        if(matrix[l / n][l % n] == target)  return true;        return false;    }};

果不其然的一遍过，在循环的时候保持区间内必须有3个及以上的数，然后退出循环后再判断是个好方法~