Find Minimum in Rotated Sorted Array

Description

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

(i.e.,0 1 2 4 5 6 7might become4 5 6 7 0 1 2).

Find the minimum element.

Notice

You may assume no duplicate exists in the array.

Example

Given[4, 5, 6, 7, 0, 1, 2]return0

Related problems

Find Minimum in Rotated Sorted Array II

Search in Rotated Sorted Array II

Implementation

Link: http://lintcode.com/en/problem/strstr/

class Solution {
public:
    /**
     * @param num: a rotated sorted array
     * @return: the minimum number in the array
     */
    int findMin(vector<int> &num) {
        // write your code here
        if(num.size() == 0) return -1;

        int start = 0, end = num.size() - 1;

        while(start + 1 < end){
            int mid = start + (end - start)/2;

            if(num[mid] > num[end]){
                start = mid;
            }else{
                end = mid;
            }
        }

        if(num[start] <= num[end]) {
            return num[start];
        } else {
           return num[end];
        }
    }
};