74. Search a 2D Matrix

这道题题目要求很简单，说白了就是二维数组的二分查找，代码如下

import java.util.Random;/** * Created by zhangwd4 on 2017/11/23. */public class LeetCode74 {    public boolean searchMatrix(int[][] matrix, int target) {        if (matrix == null)            return false;        int row = matrix.length;        if (row == 0)            return false;        int col = matrix[0].length;        if (col == 0)            return false;        int start = 0, end = row * col - 1;        while (start <= end) {            int mid = (start + end) / 2;            int midValue = matrix[mid / col][mid % col]; //这里表示第x行，第y个。            if (midValue == target) {                return true;            } else if (midValue < target) {                start = mid + 1;            } else {                end = mid - 1;            }        }        return false;    }    public static void main(String args[]) {        int n = 0;        int[][] intss = new int[3][3];        for (int i = 0; i < intss.length; i++) {            for (int j = 0; j < intss[0].length; j++) {                n += new Random().nextInt(5) + 1;                intss[i][j] = n;            }        }        for (int i = 0; i < intss.length; i++) {            for (int j = 0; j < intss[0].length; j++) {                System.out.print(intss[i][j] + "-");            }            System.out.println();        }        boolean b = new LeetCode74().searchMatrix(intss, 4);        System.out.println(b);    }}