08--search-in-rotated-sorted-array.java

class Solution {
    public int search(int[] nums, int target) {
        int left = 0;
        int right = nums.length - 1;
        while (left <= right) {
            int mid = left + (right - left) / 2; 
            if (nums[mid] == target) return mid;
            if (nums[left] <= nums[mid]) { // left to right is sorted
                if (nums[left] <= target && target < nums[mid])
                    right = mid - 1;
                else
                    left = mid + 1;
            } else { // mid to right is sorted
                if (nums[mid] < target && target <= nums[right])
                    left = mid + 1;
                else
                    right = mid - 1;
            }
        }
        return -1;
    }
} // TC: O(log n), SC: O(1)