题目：

题解：

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