leetcode-74. Search a 2D Matrix

74. Search a 2D Matrix

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Question Editorial Solution

Total Accepted: 77864  Total Submissions: 230283  Difficulty: Medium

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 .

//二分查找非递归 
bool Binary_Search(vector<int> num, int len,int target){
	int low=0,hight=len-1,mid;
	while(low<=hight){
		mid=(low+hight)/2;
		if(num[mid]==target)
			return true;
		else if(num[mid]>target)
			hight=mid-1;
		else
			low=mid+1;
	}
	return false;
}

bool searchMatrix(vector<vector<int> >& matrix, int target) {
	bool isOk=false;
    for(int i=0;i<matrix.size();i++){
    	if(Binary_Search(matrix[i], matrix[i].size(),target)){
    		isOk=true;
    		return isOk;
    	}
    }
	return isOk;    
}