LintCode (159) Find Minimum in Rotated 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.

Have you met this question in a real interview? 

Yes

Example

Given [4, 5, 6, 7, 0, 1, 2] return 0

Note

You may assume no duplicate exists in the array.

二分法， 和search一样。。。其实还要更简单。。。。

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class Solution { public: /** * @param num: a rotated sorted array * @return: the minimum number in the array */ int findMin(vector<int> &num) { if (num.empty()) return -1; int beg = 0; int end = num.size()-1; if (num[beg]<num[end]) return num[beg]; while(beg+1<end){ int mid=beg+(end-beg)/2; if (num[mid]>num[beg]) beg=mid; else end=mid; } return min(num[beg],num[end]); } };