Search a 2D Matrix II

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.

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.

class Solution {
    // O(m+n) Solution
    public boolean searchMatrix(int[][] matrix, int target) {
        if (matrix == null || matrix.length < 1 || matrix[0].length < 1)
            return false;
        // Starting from top right
        int col = matrix[0].length - 1, row = 0;
        while (row <= matrix.length - 1 && col >= 0) {
            if (target == matrix[row][col])
                return true;
            else if (target < matrix[row][col]) // if target is <, then it will not be in current column
                col--;
            else if (target > matrix[row][col]) // if target is >, then it will not be in current row
                row++;
        }
        return false;
    }
}