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, returntrue.
class Solution {
public:
bool searchMatrix(vector<vector<int> > &matrix, int target) {
int m = matrix.size();
int n = matrix[0].size();
int c = n-1;
for(int r = 0;(r<m)&&(c>=0);)
{
if(matrix[r][c]>target)
{
c--;
}
else if(matrix[r][c]<target)
{
r++;
}
else
return true;
}
return false;
}
//每次比较行末，由于已经排序好，可以进行行列删除
};