Java 基础(数组线性查找,二分法查找)

数组线性查找,二分法查找

package com.klvchen.exer;

public class ArrayTest3 {
	public static void main(String[] args) {
		String[] arr = new String[] {"JJ", "DD", "MM", "BB", "GG", "AA"};
	
                //查找(或搜索)
		//线性查找
		String dest = "BK";
		
		boolean isFlag = 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: " + i);
				break;
			}
		}
		if(isFlag) {
			System.out.print("很遗憾，没有找到");
		}
		
		System.out.println();
		
		//二分法查找
		//前提：所要查找的数组必须有序
		int[] arr2 = new int[] {-98, -34, 2, 34, 54, 66, 79, 105, 210, 333};
		
		int dest1 = 33;
		int head = 0; //初始的首索引
		int end = arr2.length - 1; //初始的末索引
		boolean isFlag1 = true;
		
		while(head <= end) {
			int middle = (head + end)/2;
			
			if(dest1 == arr2[middle]) {
				System.out.print("找到了指定的元素,位置为: " +  middle);
				isFlag1 = false;
				break;
			}else if(arr2[middle] > dest1) {
				end = middle - 1;
			}else {
				head = middle + 1;
			}
		}
		if(isFlag1) {
			System.out.println("很遗憾，没有找到~");
		}
	}
}