153. Find Minimum in Rotated Sorted Array

Suppose an array sorted in ascending order 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.

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题意：找出升序数组旋转后最小值。旋转后的数组分三种情况

0 1 2 4 5 6 7
7 0 1 2 4 5 6
4 5 6 7 0 1 2

都有个特性，因为是升序所以，当nums[mid] < nums[r]的时候最小值肯定在左边了

class Solution {
public:
    int findMin(vector<int>& nums) {
        int l, r, mid;
        l = 0, r = nums.size() - 1;
        while(l <= r){
            mid = l + (r - l) / 2;
            if(nums[mid] < nums[r]){
                r = mid;
            } else if(nums[mid] > nums[r]){
                l = mid + 1;
            } else if(nums[mid] == nums[r])
                break;
        }
        return nums[l];
    }
};