题目不贴了，leetcode上有

class Solution {
public:bool findNumberIn2DArray(vector<vector<int>>& matrix, int target) {if(matrix.empty()|| matrix[0].empty())//这句话是抄的，为了针对某种算例{return false;}for(int i=0;i<matrix.size();i++){if(target < matrix[i][matrix[0].size()-1]){for(int j = 0;j<matrix[0].size();j++){if(matrix[i][j]==target){return true;}}}if(target == matrix[i][matrix[0].size()-1]){return true;}}return false;}};