Question Definition
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.
Java Solution
public boolean searchMatrix(int[][] matrix, int target) {
if(matrix.length == 0 || matrix[0].length == 0 || target < matrix[0][0])
return false;
int i = 0;
int j = 0;
while(i < matrix.length){
while(j < matrix[i].length){
if(matrix[i][j] == target) return true;
if(matrix[i][j] > target) break;
j++;
}
i++;
j = 0;
}
return false;
}
Comments