Freaks City

Swapping Nodes in Pairs Problem: Given a linked list, swap every two adjacent nodes and return its head. Iterative Approach: class ListNode { int val; ListNode next; ListNode(int val) { this.val = val; } } class Solution { public ListNode swapPairs(ListNode head) { if (head == null || head.next == null) { ...

LeetCode 343: Integer Break Given an integer n, break it into the sum of k positive integers, where k >= 2, and maximize the product of those integers. Return the maximum product you can get. Dynamic Programmign Approach The problem can be solved using dynamic programming. The key insight is that the maximum product for a number i depends on ...

Remove Linked List Elements (LeetCode 203) Given the head of a linked list and an integer val, remove all nodes where Node.val == val and return the new head node. Using a dummy head simplifies handling edge cases, especially when the head node itself needs to be removed. A traversal pointer prev is used to point to the node preceding the one c ...

24. Swap Nodes in Pairs Problem: Swap adjacent nodes in a linked list pairwise, returnnig the new head. Do not modify node values—only rewire nodes. Approaches: Iterative: Use a dummy head to track the previous node. Adjust pointers for each pair. Recursive: Swap the first two nodes, then recurce on the reamining list. class Solution: ...

Given an m x n board of characters and a list of strings words, return all words on the board. Each word must be constructed from letters of sequentially adjacent cells, where adjacent cells are horizontally or vertically neighboring. The same letter cell may not be used more than once in a word. 1. Trie with DFS Build a trie from the given wor ...

Given a string, identify the length of its longest contiguous substring containing no duplicate cahracters. Example 1: Input: "abcabcbb" Output: 3 Explanation: The longest substring without repeating characters is "abc", which has a length of 3. Example 2: Input: "bbbbb" Output: 1 Explanation: The longest substrin ...

Given a string text, the objective is to locate longest contiguous substring that reads the same forward and backward. Constraints: 1 <= text.length <= 1000 text consists of alphanumeric English characters only. Dynamic Programming Approahc 1. State Definition Define a 2D table is_palindrome[i][j] where i and j are indices. The value i ...