題目
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
.
分析
解答
class Solution {
public:
bool searchMatrix(vector<vector<int>>& matrix, int target) {
int row=matrix.size();
if(row==0)
return false;
int col=matrix[0].size();
int i=0;
int j=col-1;
while(i<row && j>=0){
if(matrix[i][j]==target){
return true;
}
else if(matrix[i][j]>target){
j=j-1;
}
else{
i=i+1;
}
}
return false;
}
};