LeetCode 240. Search a 2D Matrix II

Write an efficient algorithm that searches for a value in an m x n matrix. This matrix has the following properties:

Integers in each row are sorted in ascending from left to right.

Integers in each column are sorted in ascending from top to bottom.

For example,

Consider the following matrix:

[

[1, 4, 7, 11, 15],

[2, 5, 8, 12, 19],

[3, 6, 9, 16, 22],

[10, 13, 14, 17, 24],

[18, 21, 23, 26, 30]

]

Given target = 5, return true.

Given target = 20, return false.

题目大意：编写一个有效的算法，在m×n矩阵中搜索一个值。
该矩阵具有以下属性：
每行中的整数从左到右依次排列。每列中的整数按从上到下的顺序排列。
分析：对每一行进行binary_serch()，如果能够找到则return
true，否则返回false

class Solution {
public:
bool searchMatrix(vector<vector<int>>& matrix, int target) {
for(int i = 0; i < matrix.size(); i++)
if (binary_search(matrix[i].begin(), matrix[i].end(), target)) return true;
return false;
}
};