折半查找

 1 public class Solution {
 2 
 3     public static int BinarySearch(int[] sz,int key){
 4         int low = 0;
 5         int high = sz.length - 1;
 6         
 7         while (low <= high) {
 8             int middle = (low + high) / 2;
 9             if(sz[middle] == key){
10                 return middle;
11             }else if(sz[middle] > key){
12                 high = middle - 1;
13             }else {
14                 low = middle + 1;
15             }
16         }
17         return -1;
18     }
19 }