[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.

递归

class Solution {public:    int findMin(vector<int> &num) {        int n = num.size() - 1;        if(num.size() == 1 || num[0] < num[n]) return num[0];//先考虑特殊情况        return find(0,n,num);    }    int find(int first,int end,vector<int> &num){        int mid = (first + end)/2;        if(num[mid] < num[mid - 1] && num[mid] <= num[end])            return num[mid];        if(num[mid] >= num[first] && num[mid] >= num[end])            return find(mid + 1,end,num);        else return find(first,mid - 1,num);    }};

二分法

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