LeetCode.33

Search 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 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.

int half(vector<int>& nums, int target, int begin, int end){int p = (begin + end) / 2;if(nums[begin] == target) return begin;if(nums[p] == target) return p;if(nums[end] == target) return end;if(nums[begin] < nums[p]){if(nums[begin] < target && target < nums[p]){return half(nums, target, begin, p);}else{return half(nums, target, p, end);}}else if(nums[begin] == nums[p]){return -1;}if(nums[p] < nums[end]){if(nums[p] < target && target < nums[end]){return half(nums, target, p, end);}else{return half(nums, target, begin, p);}}return -1;}int search(vector<int>& nums, int target){if(nums.empty()){return -1;}return half(nums, target, 0, nums.size() - 1);}