leetcode_74题——Search a 2D Matrix（数组查找）

Search a 2D Matrix

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Question Solution

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 from left to right.

The first integer of each row is greater than the last integer of the previous row.

For example,

Consider the following matrix:

[
[1,   3,  5,  7],
[10, 11, 16, 20],
[23, 30, 34, 50]
]

Given target =

3

, return

true

.

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#include<iostream>
#include <vector>
using namespace std;

/*这道题是在一个排好序的数组中查找一个指定的数
从上到下递增，从左到右递增，所以从右往左，每次与最上面的那个数作比较*/
bool searchMatrix(vector<vector<int>>& matrix, int target) {
int x=matrix.size();
int y=matrix[0].size();

for(int j=y-1;j>=0;j--)
{
if(target==matrix[0][j])
return true;
if(target>matrix[0][j])
{
for(int i=1;i<=x-1;i++)
if(target==matrix[i][j])
return true;
}
}
return false;
}

int main()
{
vector<vector<int> > vec0;
vector<int> vec;
vec.push_back(1);
vec0.push_back(vec);
vec.clear();
vec.push_back(3);
vec0.push_back(vec);
cout<<searchMatrix(vec0,3)<<endl;

}