题目：

题解：

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