顺序查找+二分查找

1.顺序查找

public static int indexOf(int[]a,int v){
        int ret=-1;
        int i=0;
        while(i<a.length){
            if(a[i]==v)
                ret=i;
            i++;
        }
        return ret;
    } 

2.二分查找（左闭右闭）

public static int binarySearch(int a[],int v){
        int ret=-1;
        int left=0;
        int right=a.length-1;
        while(left<right){
            int mid=(left+right)/2;
            if(a[mid]==v)
                ret=mid;
            if(a[mid]>v)
                right=mid-1;
            else
                left=mid+1;
        }
        return ret;
    }