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) {        if(matrix == null || matrix.length < 1 || matrix[0].length <1) {            return false;        }        int col = matrix[0].length-1;        int row = 0;        while(col >= 0 && row <= matrix.length-1) {            if(target == matrix[row][col]) {                return true;            } else if(target < matrix[row][col]) {                col--;            } else if(target > matrix[row][col]) {                row++;            }        }        return false;    }}复制代码