LC33.java

/*
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.

Your algorithm's runtime complexity must be in the order of O(log n).

Example 1:

Input: nums = [4,5,6,7,0,1,2], target = 0
Output: 4
Example 2:

Input: nums = [4,5,6,7,0,1,2], target = 3
Output: -1
*/

class Solution {
    public int search(int[] nums, int target) {
        int n = nums.length;
        int left = 0;
        int right = n - 1;
        int mid;

        while (left <= right)
        {
            mid = ((left + right) / 2);

            if (nums[mid] == target)
                return mid;

            else if (nums[mid] >= nums[left])
            {
                if (target <= nums[mid] && target >= nums[left])
                    right = mid - 1;
                else
                    left = mid + 1;
            }
            else
            {
                if (target >= nums[mid] && target <= nums[right])
                    left = mid + 1;
                else
                    right = mid - 1;
            }
        }

        return -1;
    }
}