二分查找（递归和非递归方式）

public class erfenchazhao {
    public static void main(String[] args) {
        int [] num ={1, 2, 2, 3, 4, 5, 7, 9, 10, 11};
        int search = search(num, 14);
        System.out.println(search);
        //--------------------------
        int max = num.length - 1;
        int min =0;
        int search2 = search2(num, max, min, 6);
        System.out.println(search2);
    }
    //递归
    private static int search2(int[] num, int max, int min ,int i) {

        int index =(max+min)/2;
        if(max >= min){
            if(num[index]== i){
                return index +1;
            }else if (num[index]>i){
                search2(num,index-1,min,i);
            }else {
                search2(num,max,index+1,i);
            }
        }
        return -1;
    }

    //非递归
    private static int search(int[] num, int i) {
        int length = num.length-1;
        int start = 0;
        while (start <= length){
            int index = (length+start)/2;
            if(num[index] == i){
                return index+1;
            }else if (num[index] >i){
                length = index-1;
            }else{
                start = index+1;
            }
        }
        return -1;
    }
}