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.

Analysis:

public class Solution {
    public int search(int[] A, int target) {
        int l = 0;
        int r = A.length - 1;
        while (l <= r) {
            int m = (l + r) / 2;
            if (A[m] == target) {
                return m;
            }
            if (A[m] >= A[l]) {
                if (A[l] <= target && target < A[m]) {
                    r = m - 1;
                } else {
                    l = m + 1;
                }
            } else {
                if (A[m] < target && target <= A[r]) {
                    l = m + 1;
                } else {
                    r = m - 1;
                }
            }
        }
        return -1;
    }
}

Note:

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Search in Rotated Sorted Array II

Follow up for “Search in Rotated Sorted Array”:
What if duplicates are allowed?

Would this affect the run-time complexity? How and why?

Write a function to determine if a given target is in the array.

Reference

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