LeetCode 240. Search a 2D Matrix II

240. Search a 2D Matrix II

Description

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.

Analysi

这道题的题意很简单，就是给定一个数，然后寻找这个数是不是存在于给定的二维数组中，如果存在则返回true，不存在则返回false。这道题我一开始尝试了一下直接利用两个循环可不可以accepted，结果发现是可以的= = 。下面是我的代码。

Code

class Solution {
public:
bool searchMatrix(vector<vector<int>>& matrix, int target) {
int len  = matrix.size();
if(len == 0) return false;
int len2 = matrix[0].size();
if(len2==0) return false;
int res = 0;

for(int i = 0 ;i < len;++i){
for(int j = 0 ; j<len2;++j){
if(target == matrix[i][j]) {
return true;
}
}
}

return false;
}
};