leetcode JAVA Search a 2D Matrix 难度系数3 3.25

Question：

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.

public class Solution {   public boolean searchMatrix(int[][] matrix, int target) {int row = matrix.length;int col = matrix[0].length;int[] temp = new int[row * col];int count = 0;for (int i = 0; i < row; i++) {for (int j = 0; j < col; j++) {temp[count++] = matrix[i][j];}}int low = 0;int high = row * col-1;int mid = -1;while (low <= high) {mid = (low + high) / 2;if (temp[mid] == target) {return true;} else if (temp[mid] > target) {high = mid - 1;} else {low = mid + 1;}}return false;}}

public class Solution {   public boolean searchMatrix(int[][] matrix, int target) {int row = matrix.length;int col = matrix[0].length;int low = 0;int high = row * col - 1;int mid = -1;while (low <= high) {mid = (low + high) / 2;if (matrix[mid/col][mid%col] == target) {return true;} else if (matrix[mid/col][mid%col] > target) {high = mid - 1;} else {low = mid + 1;}}return false;   }}