二分查找算法

二分查找算法

package com.xmetc.lhg; import java.util.Arrays; import java.util.Scanner; /** * @author lhg * */ public class Test { /** * @param args */ public static void main(String[] args) { int[] arr = new int[10]; int key; Scanner scanner = new Scanner(System.in); System.out.println("Please input each array: "); for (int i = 0; i < arr.length; i++) { arr[i] = scanner.nextInt(); } System.out.println("Plese input the key: "); key = scanner.nextInt(); Arrays.sort(arr); for (int i = 0; i < arr.length; i++) { System.out.print(arr[i] + " "); } System.out.println(); int local = binarySearch(arr, key); System.out.println(local); } /** * 二分查找 * @param array * @param key * @return */ public static int binarySearch(int[] array,int key) { int low = 0; int high = array.length-1; while (low <= high) { int mid = (low+high) / 2; int midval = array[mid]; if (midval < key) { low = mid + 1; } else if (midval > key) { high = mid - 1; } else { return mid; } } return -1; } }