153. Find Minimum in Rotated Sorted Array

Suppose an array of length n sorted in ascending order is rotated between 1 and n times. For example, the array nums = [0,1,2,4,5,6,7] might become:

• [4,5,6,7,0,1,2] if it was rotated 4 times.
• [0,1,2,4,5,6,7] if it was rotated 7 times.

Notice that rotating an array [a[0], a[1], a[2], …, a[n-1]] 1 time results in the array [a[n-1], a[0], a[1], a[2], …, a[n-2]].

Given the sorted rotated array nums of unique elements, return the minimum element of this array.

You must write an algorithm that runs in O(log n) time.

class Solution {
public:
    int findMin(vector<int>& nums) {
        int l = 0, r = nums.size() - 1;
        while(l <= r) {
            int m = l + (r-l)/2;
            int L = m - 1 >= 0 ? nums[m-1] : INT_MAX;
            int R = m + 1 < nums.size() ? nums[m+1] : INT_MAX;
            if(L >= nums[m] and nums[m] <= R) return nums[m];
            else if(nums[m] < nums[r])
                r = m - 1;
            else l = m + 1;
        }
        return INT_MIN;
    }
};