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],[23,30,34,60]], target = 3
Output: true
Example 2:
Input: matrix = [[1,3,5,7],[10,11,16,20],[23,30,34,60]], target = 13
Output: false
Constraints:
- m == matrix.length
- n == matrix[i].length
- 1 <= m, n <= 100
- -104 <= matrix[i][j], target <= 10^4
Solution
class Solution {
public boolean searchMatrix(int[][] matrix, int target) {
int cols = matrix.length;
int rows = matrix[0].length;
int lo = 0;
int hi = cols * rows - 1;
while (lo <= hi) {
int mid = lo + (hi - lo) / 2;
int value = matrix[mid / rows][mid % rows];
if (value == target) {
return true;
}
if (target < value) {
hi = mid - 1;
} else {
lo = mid + 1;
}
}
return false;
}
}