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.

二分法来实现分半查找

 

1. int findMin(vector<int> &num) {
2. int n_size = num.size();
3. if(n_size == 0) return 0;
4. if(n_size == 1) return num[0];
5. int start = 0;
6. int end = n_size-1;
7. while(num[start] > num[end]) {
8. if(end - start == 1) {
9. return num[end];
10. }
11. int mid = start + ((end-start)>>1);
12. if(num[mid] > num[end]) {
13. start = mid;
14. } else {
15. end = mid;
16. }
17. }
18. return num[start];
19. }