Title
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. Example 1:
Input:
matrix = [
[1, 3, 5, 7],
[10, 11, 16, 20],
[23, 30, 34, 50]
]
target = 3
Output: true
Example 2:
Input:
matrix = [
[1, 3, 5, 7],
[10, 11, 16, 20],
[23, 30, 34, 50]
]
target = 13
Output: false
以前做过，其实可以参考我的另一个bloglink
Solution
//cpp:
class Solution {
public:
bool searchMatrix(vector<vector<int>>& matrix, int target) {
int n = matrix.size();
if(n==0)
return false;
int m = matrix[0].size();
int i = n - 1,j = 0;
while (0<=i&&j<m)
{
if (matrix[i][j] == target) {
return true;
}
else if (matrix[i][j] < target) {
j++;
}
else {
i--;
}
}
return false;
}
};