Search In Rotated Sorted Array

interview_workbook/leetcode/binary_search /app/src/interview_workbook/leetcode/binary_search/search_in_rotated_sorted_array.py
View Source

Algorithm Notes

Summary: Search In Rotated Sorted Array — notes not yet curated.
Time: Estimate via loops/recurrences; common classes: O(1), O(log n), O(n), O(n log n), O(n^2)
Space: Count auxiliary structures and recursion depth.
Tip: See the Big-O Guide for how to derive bounds and compare trade-offs.

Big-O Guide

Source

"""
Search In Rotated Sorted Array

Problem: Search in Rotated Sorted Array
LeetCode link: https://leetcode.com/problems/search-in-rotated-sorted-array/
Description: Given a rotated sorted array of distinct integers, return the index of the target if it exists, otherwise return -1. Must run in O(log n) time.
"""

from src.interview_workbook.leetcode._registry import register_problem
from src.interview_workbook.leetcode._types import Category, Difficulty


class Solution:
    def search(self, nums: list[int], target: int) -> int:
        """Search in rotated sorted array."""
        left, right = 0, len(nums) - 1
        while left <= right:
            mid = (left + right) // 2
            if nums[mid] == target:
                return mid
            if nums[left] <= nums[mid]:
                if nums[left] <= target < nums[mid]:
                    right = mid - 1
                else:
                    left = mid + 1
            else:
                if nums[mid] < target <= nums[right]:
                    left = mid + 1
                else:
                    right = mid - 1
        return -1


def demo():
    """Run a demo for the Search In Rotated Sorted Array problem."""
    solver = Solution()
    nums = [4, 5, 6, 7, 0, 1, 2]
    target = 0
    result = solver.search(nums, target)
    return str(result)


register_problem(
    id=33,
    slug="search_in_rotated_sorted_array",
    title="Search in Rotated Sorted Array",
    category=Category.BINARY_SEARCH,
    difficulty=Difficulty.MEDIUM,
    tags=["array", "binary_search"],
    url="https://leetcode.com/problems/search-in-rotated-sorted-array/",
    notes="",
)