[LeetCode]Search in Rotated Sorted Array

Search 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).

You are given a target value to search. If found in the array return its index, otherwise return -1.

You may assume no duplicate exists in the array.

二分搜索，好好理解里面的逻辑吧。

class Solution {
public:
    int search(vector<int>& nums, int target) {
        if(nums.size()==0) return -1;
        int left=0,right=nums.size()-1;
        while(left<=right)
        {
            int mid = (left+right)/2;
            if(nums[mid]==target) return mid;
            if(nums[mid]>nums[left])
            {
                if(target <= nums[mid] && target >= nums[left]) right = mid - 1;
                else left = mid + 1;
            }
            else if(nums[mid]<nums[left])
            {
                if(target >= nums[left] || target <= nums[mid]) right = mid -1;
                else left = mid + 1;
            }
            else left ++;
        }
        return -1;
    }
};