Search in Rotated Sorted Array II in Python

Consider we have an array sorted in ascending order. That is rotated at some pivot unknown to us beforehand. For example, if the array is like [0,0,1,2,2,5,6], this might become [2,5,6,0,0,1,2]. We have a target value to search. If that is found in the array, then return true, otherwise return false. So if the array is like [2,5,6,0,0,1,2], and target is 0, then the output will be 0

Let us see the steps −

• low := 0 and high := size of array
• while low < high
  • mid := low + (high - low)/2
  • if nums[mid] = target, then return true
  • if nums[low] = nums[mid] and nums[high - 1] = nums[mid], then
    • increase low by 1 and decrease high by 1, and continue for the next iteration
  • if nums[low] <= nums[mid], then
    • if target >= nums[low] and target &miinus; nums[mid], then high := mid, otherwise low := mid + 1
  • Otherwise
    • if target <= nums[high - 1] and target > nums[mid], then low := mid + 1, otherwise high := mid
• return false

Let us see the following implementation to get better understanding −

Example

 Live Demo

class Solution(object):
   def search(self, nums, target):
      low = 0
      high = len(nums)
      while low<high:
         mid = low + (high-low)//2
         if nums[mid] == target:
            return True
         if nums[low] == nums[mid] and nums[high-1] == nums[mid]:
            low +=1
            high -=1
            continue
         if nums[low]<=nums[mid]:
            if target >=nums[low] and target <nums[mid]:
               high = mid
            else:
               low = mid+1
         else:
            if target<=nums[high-1] and target>nums[mid]:
               low = mid+1
            else:
               high = mid
      return False
ob1 = Solution()
print(ob1.search([2,5,6,0,0,1,2], 0))

Input

[2,5,6,0,0,1,2]
0

Output

True

Arnab Chakraborty

Published on 28-Apr-2020 11:02:03

• Related Questions & Answers
• Search in Rotated Sorted Array II in C++
• Search in Rotated Sorted Array in Python
• Find Minimum in Rotated Sorted Array II in C++
• Check if an array is sorted and rotated in Python
• Find Minimum in Rotated Sorted Array in C++
• Word Search II in Python
• Program to check whether an array Is sorted and rotated in Python
• Find the Rotation Count in Rotated Sorted array in C++
• Maximum element in a sorted and rotated array in C++
• Check if an array is sorted and rotated in C++
• Remove Duplicates from Sorted Array II in C++
• Convert Sorted Array to Binary Search Tree in Python
• Search a 2D Matrix II in Python
• Finding smallest element in a sorted array which is rotated in JavaScript
• Search elements in a sorted object array in Java