Find Minimum in Rotated Sorted Array

LeetCode: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.

解法一：遍历。。。时间复杂度O(n)

<span style="white-space:pre">	</span>int res = num[0];
	for(int i=1; i<num.size(); i++)
	{
		if(num[i]<res)
			return num[i];
	}

	return res;

解法二：二分法查找

<span style="white-space:pre">	</span>int begin = 0;
	int end = num.size()-1;
	int mid=begin;

	while(num[begin] > num[end])
	{
		if(end - begin == 1)
		{
			mid = end;
			break;
		}
		mid = (begin+end)/2;
		if(num[mid]>num[begin])
		{
			begin = mid;
		}
		else if(num[mid]<num[end])
		{
			end = mid;
		}
	}

	return num[mid];