线性查找与二分查找

package com.yao.exer;
/*
 * 数组复制反转遍历
 * 线性查找
 * 二分查找
 */
public class ArrayExer6 {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		String[] arr = new String[] {"JJ","DD","BB","AA","PP","QQ"};
		//数	组的复制
		String[] arr1 = new String[arr.length];
		for(int i = 0;i < arr.length;i++) {
			arr1[i] = arr[i];
		}
		//数组的反转
		//方式一
		for(int i = 0;i < arr.length/2;i++) {
			String temp = arr[i];
			arr[i] = arr[arr.length-i-1];
			arr[arr.length-i-1] = temp;
		}
		//方式二
//		for(int i = 0,j = arr.length-1;i < j;i++,j--) {
//			String temp = arr[i];
//			arr[i] = arr[j];
//			arr[j] = temp;
//		}
		//遍历arr
		for(int i = 0;i<arr.length;i++) {
			System.out.print(arr[i]+"\t");
		}
		System.out.println();
		//线性查找
		String dest = "CC";
		boolean flag = true;
		for(int i = 0;i < arr.length;i++) {
			if(dest.equals(arr[i])) {
				System.out.println("找到了指定的元素，位置为"+i);
				flag = false;
				break;
			}
		}
		if(flag == true) {
			System.out.println("很遗憾没找到");
		}
		//二分法查找:前提是数组必须有序
		int[] arr2 = new int[] {-98,-43,-2,0,2,7,12,36,78,99,143,324};
		int desk1 = 78;
		int head = 0;//初始首索引
		int end = arr2.length - 1;//初始末索引
		flag = true; 
		while(head<=end) {
			int middle = (head + end)/2;
			if(desk1 == arr2[middle]) {
				System.out.println("找到了指定的元素，位置为:" + middle);
				flag = false;
				break;
			}
			else if(arr2[middle] > desk1) {
				end = middle - 1;
			}
			else if(arr2[middle] < desk1) {
				head = middle + 1;
			}
		}
		if(flag == true) {
			System.out.println("很遗憾没找到");
		}
		

	}

}