旋转数组的最小数字

题目：把一个数组最开始的若干个元素搬到数组的末尾，我们称之为数组的旋转。输入一个递增排序的的数组的旋转，输出旋转数组的最小元素，如{3,4,5,1,2}位{1,2,3,4,5}的数组旋转。最小值是1

思路：用二分查找法

#include<iostream>
#include<string>
#include<cstring>
#include<cstdlib>
#include<cstdio>
using namespace std;
/**
 * Definition for binary tree
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 * };
 */
class Solution {
public:
    int minNumberInRotateArray(vector<int> rotateArray) {
        if(rotateArray.size()==1) return rotateArray[0];
        int index_left  =0,index_right = rotateArray.size()-1;
        int mid = index_left;
        while(rotateArray[index_left]>=rotateArray[index_right]){
            if(index_left +1 == index_right) {
                return rotateArray[index_right];
            }
            mid = (index_left +index_right)/2;
            if(rotateArray[index_left]==rotateArray[index_right]&&rotateArray[index_left]==rotateArray[mid]){
                int result = rotateArray[index_left];
                for(int i = index_left+1;i<=index_right;i++){
                        if(result> rotateArray[i]) result = rotateArray[i];
                }
                return result;
            }
            if(rotateArray[mid]>=rotateArray[index_left]){
                index_left = mid;
            }else index_right = mid;
        }
        return rotateArray[mid];
    }
};