【二分查找】278. 第一个错误的版本

 1 // The API isBadVersion is defined for you.
 2 // bool isBadVersion(int version);
 3 
 4 class Solution {
 5 public:
 6     int firstBadVersion(int n) 
 7     {
 8         int l=0;
 9         int r=n;
10         while(l < r)
11         {
12             int m = l + (r - l) / 2;
13             if(isBadVersion(m))
14             {
15                 r=m;
16             }
17             else 
18             {
19                 l = m + 1;
20             }
21         }
22         return l;   
23     }
24 };