模板 二分

 1 int binsearch(int *t,int k,int n)
 2 {
 3     //t为数组，k是要查找的数，n为长度，此为升序
 4 
 5     int low = 1,high = n,mid;
 6 
 7     while(low<=high)
 8     {
 9         mid = (low+high)/2;
10         if(k == t[mid])
11         return mid;
12         else if(k<t[mid])
13         high = mid-1;
14         else
15         low = mid+1;
16     }
17 
18     return -1;
19 
20 }