题目描述

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

class Solution {public:    bool searchMatrix(vector
     
      
       > &matrix, int target) {        if(matrix.size() == 0) return false;                int m = matrix.size();        int n = matrix[0].size();                  int index = -1;        for(int i =0;i
       
        = target)            {                index = i;                break;            }        }        if(index == -1)return false;                for(int j = 0;j<=n-1;j++){            if(matrix[index][j]==target)                return true;        }        return false;    }};
       
      
     

 

true.