Search a 2D Matrix II leetcode

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.

public class Solution {
    public boolean searchMatrix(int[][] matrix, int target) {
        int m = matrix.length - 1;
        int n = 0;
        while (m >= 0 && n < matrix[0].length) {
            if (matrix[m][n] == target) {
                return true;
            } else if (matrix[m][n] > target) {
                m--;
            } else {
                n++;
            }
        }
        return false;
    }
}