【LeetCode】Find Minimum in Rotated Sorted Array 在旋转数组中找最小数

Add Date 2014-10-15

Find Minimum in Rotated Sorted Array

Suppose a sorted array is rotated at some pivot unknown to you beforehand.

(i.e., 0 1 2 4 5 6 7 might become 4 5 6 7 0 1 2).

Find the minimum element.

You may assume no duplicate exists in the array.

这个很简单，因为没有重复数字，数组本质上还是有序的，用类似二分查找的方法复杂度O(log n)。code 也没几行，直接看 code 吧，记得考虑一下整个数组没有 rotated 的情况。

 1 class Solution {
 2 public:
 3     int findMin(vector<int> &num, int pre, int post) {
 4         if(pre == post)
 5             return num[pre];
 6         if(num[pre] < num[post])
 7             return num[pre];
 8         int mid = (pre+post)/2;
 9         if(num[mid] >= num[pre])
10             return findMin(num, mid+1, post);
11         if(num[mid] < num[post])
12             return findMin(num, pre, mid);
13     }
14     int findMin(vector<int> &num) {
15         int len = num.size();
16         return findMin(num, 0, len-1);
17     }
18 };

明天继续刷LeetCode。。