Leetcode#34 Search for a Range

原题地址

 

二分搜索变种

代码：

 1 vector<int> searchRange(int A[], int n, int target) {
 2         vector<int> range(2, -1);
 3         int l, r;
 4         
 5         // left
 6         l = 0;
 7         r = n - 1;
 8         while (l <= r) {
 9             int m = (l + r) / 2;
10             if (A[m] < target)
11                 l = m + 1;
12             else
13                 r = m - 1;
14         }
15         if (l < n && A[l] == target)
16             range[0] = l;
17         
18         // right
19         l = 0;
20         r = n - 1;
21         while (l <= r) {
22             int m = (l + r) / 2;
23             if (A[m] > target)
24                 r = m - 1;
25             else
26                 l = m + 1;
27         }
28         if (r >= 0 && A[r] == target)
29             range[1] = r;
30             
31         return range;
32 }

 

posted @ 2015-01-28 14:43  李舜阳  阅读(138)  评论(0)  编辑  收藏  举报