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 7might become4 5 6 7 0 1 2).

Find the minimum element.

You may assume no duplicate exists in the array.

分析

最后一个词作为target,然后找第一个<=target的数字

class Solution {
    public int findMin(int[] nums) {
        if(nums == null || nums.length == 0){
            return -1;
        }
        int s = 0, e = nums.length - 1, target = nums[nums.length - 1];

        while(s + 1 < e){
            int m = s + (e - s)/2;
            //first <= target
            if(nums[m] <= target){
                e = m;
            }else{
                s = m;
            }           
        }

        if(nums[s] <= target)
            return nums[s];

        else
            return nums[e];
    }
}

python

class Solution:
    def findMin(self, nums: List[int]) -> int:
        if not nums:
            retunr -1
        t = nums[-1]
        s,e = 0,len(nums)-1
        while s <= e:
            m = (s+e)//2
            if nums[m] <= t:
                e = m -1
            else:
                s = m + 1
        return nums[s]