package com.liuhuan.study.algorithms.search;
/**
* @author LiuHuan
* @date 2020-07-09 14:35
* @desc 二分查找非递归
*/
public class BinarySearchNoRecur {
public static void main(String[] args) {
//测试
int[] arr = {1, 3, 8, 10, 11, 67, 100};
int index = binarySearch(arr, 100);
System.out.println("index=" + index);
}
/**
* 二分查找的非递归实现
*
* @param arr 待查找的数组, arr是升序排序
* @param target 需要查找的数
* @return 返回对应下标,-1表示没有找到
*/
public static int binarySearch(int[] arr, int target) {
int left = 0;
int right = arr.length - 1;
//说明继续查找
while (left <= right) {
int mid = (left + right) / 2;
if (arr[mid] == target) {
return mid;
} else if (arr[mid] > target) {
//需要向左边查找
right = mid - 1;
} else {
//需要向右边查找
left = mid + 1;
}
}
return -1;
}
}