LeetCode 74 Search a 2D Matrix with java solution

description：
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.
For example,

Consider the following matrix:

[
[1, 3, 5, 7],
[10, 11, 16, 20],
[23, 30, 34, 50]
]
Given target = 3, return true.

使用二分法完美解决

public class Solution {    public boolean searchMatrix(int[][] matrix, int target) {        if (matrix == null || matrix.length == 0) {            return false;        }        if (matrix[0] == null || matrix[0].length == 0) {            return false;        }        int cow = matrix.length;        int column = matrix[0].length;        int start = 0;        int end = cow * column - 1;        while (start + 1 < end) {            int mid = start + (end - start) / 2;            int number = matrix[mid / column][mid % column];            if (number < target) {                start = mid;            } else {                end = mid;            }        }        if (matrix[start / column][start % column] == target) {            return true;        }        if (matrix[end / column][end % column] == target) {            return true;        }        return false;    }}