Java 二分法查询

使用场景：数据量大，有序不可重复的查询

package com.datastruct.array;
/**
 * 有序数组
 */
public class OrderArray {

    public static void main(String[] args) {
        int[] mm = {1,5,9,10,25,36};
        System.out.println(binarySearch(mm,24));
    }
    
    public static int binarySearch(int[] arr,int searchValue){
        //默认数组第一个元素项
        int lowerBound = 0;
        //数组最后一个元素项
        int upperBound = arr.length-1;
        //数组中间元素项
        int curtIndex;
        //每循环一次，范围缩小一半
        while (true){
            curtIndex = (lowerBound+upperBound)/2;
            if (arr[curtIndex]==searchValue){
                return curtIndex;
            }else if(lowerBound>upperBound){
                return -1;//未找到
            }else{
                if (arr[curtIndex]<searchValue){
                    //数组后半部分查询
                    lowerBound = curtIndex+1;
                }else{
                    //数组前半部分查询
                    upperBound = curtIndex-1;
                }
            }
        }
    }
}