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; }