[email protected] [33] Search in Rotated Sorted Array

https://leetcode.com/problems/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.

class Solution {
public:
    int search(vector<int>& nums, int target) {
        if(nums.size() == 0) return -1;
        if(nums.size() == 1) return target==nums[0]? 0: -1;

        int low = 0, high = nums.size()-1, breakPoint = nums.size()-1;
        while(high - low > 1) {
            int mid = (low + high)/2;
            if(nums[mid] > nums[high]) low = mid;
            else high = mid;
        }
        breakPoint = low;
        cout<<breakPoint<<endl;

        low = 0, high = breakPoint;
        while(low <= high) {
            int mid = (low + high)/2;
            if(nums[mid] == target) return mid;
            else if(nums[mid] < target) low = mid+1;
            else high = mid-1;
        }

        low = breakPoint+1; high = nums.size()-1;
        while(low <= high) {
            int mid = (low + high)/2;
            if(nums[mid] == target) return mid;
            else if(nums[mid] < target) low = mid+1;
            else high = mid-1;
        }

        return -1;
    }
};