Quiz on Data Structure

• TBD

CodingBat

• Go to (CodingBat.com)[https://www.codingbat.com/python] and create an account and log into the website.
• Start to solve problems. If you are new, the Warmup-1 is a good place to start.
• Let’s solve problems in the CodingBat.com website for 45 minutes.

  Explore - Linked List Cycle

Linked List Cycle

Approach 1 - Hash Table

class Solution:
    def hasCycle(self, head: ListNode) -> bool:
        seen = set()
        cur = head
        while cur:
            if cur in seen:
                return True
            seen.add(cur)
            cur = cur.next
        return False

Approach 2 - Two Poiners

class Solution:
    def hasCycle(self, head: ListNode) -> bool:
        slow = fast = head
        while slow and fast and fast.next:
            slow = slow.next
            fast = fast.next.next
            if slow == fast:
                return True
        return False

LinkedList - Explore

LinkedList - Summary

• Two Pointers (Fast & Slow)
• Iterate
• Reverse

HackerRank

• Python

https://www.hackerrank.com/domains/python?filters%5Bstatus%5D%5B%5D=unsolved&filters%5Bsubdomains%5D%5B%5D=py-sets&filters%5Bsubdomains%5D%5B%5D=py-collections&badge_type=python

Stack

LeetCode problems

https://leetcode.com/explore/learn/card/queue-stack/230/usage-stack/1394/

(Minimum Stack)[https://leetcode.com/problems/min-stack/]

(Valid Parenthesis)[https://leetcode.com/problems/valid-parentheses/]

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