Problem Given a binary search tree (BST), find the lowest common ancestor (LCA) of two given nodes in the BST. Definiton Lowest Common Ancestor Definition Problems related to it - Lowest Common Ancestor Definition Examples Example 1: graph TD; 6; 6 --- 2; 6 --- 8; 2 --- 0; 2 --- 4; 8 --- 7; 8 --- 9; 4 --- 3; 4 --- 5; style 2 fill:#FF9933 style 8 fill:#FF9933 style 6 fill:#3399FF ...
Problem Given a binary tree, find the diameter of it. Definition Diameter of tree is defined as a longest path or route between any two nodes in a tree. The path may or may not for through the root. Example Example 1: 1 / \ 2 3 / \ 4 5 Input: root = [1,2,3,4,5] Output: 3 Explanation: 3 is the length of the path [4,2,1,3] or [5,2,1,3]. ...
Problem Given the head of a linked list, reverse the nodes of the list k at a time, and return the modified list. k is a positive integer and is less than or equal to the length of the linked list. If the number of nodes is not a multiple of k then left-out nodes, in the end, should remain as it is. You may not alter the values in the list’s nodes, only nodes themselves may be changed. ...
Problem Given head, the head of a linked list, determine if the linked list has a cycle in it. Return true if there is a cycle in the linked list. Otherwise, return false. Examples Example 1 Input: head = [0, 1, 3, 2, 4] output: true Explanation: Cycle starts at node 2 ...
Maximum Depth of Binary Tree Problem Given a binary tree, find its maximum depth. Definition A binary tree’s maximum depth is the number of nodes along the longest path from the root node down to the farthest leaf node. The number of nodes along the longest path from the root node down to the farthest leaf node. Depth of root node is 0. Example Example 1 ...
Problem You are given a perfect binary tree where all leaves are on the same level, and every parent has two children. The binary tree has the following definition: struct Node { int val; Node *left; Node *right; Node *next; } Populate each next pointer to point to its next right node. If there is no next right node, the next pointer should be set to NULL. ...
Problem Given the roots of two binary trees p and q, write a function to check if they are the same or not. Two binary trees are considered the same if they are structurally identical, and the nodes have the same value. Example Input: Two binary Search Trees ...
Problem Given the root of a binary tree, return the preorder traversal of its nodes’ values. Examples Example 1: 1 \ 2 / 3 Input: root = [1,null,2,3] Output: [1,2,3] ...
Problem Alice and Bob play a game with piles of stones. There are an even number of piles arranged in a row, and each pile has a positive integer number of stones piles[i]. The objective of the game is to end with the most stones. The total number of stones across all the piles is odd, so there are no ties. Alice and Bob take turns, with Alice starting first. Each turn, a player takes the entire pile of stones either from the beginning or from the end of the row. This continues until there are no more piles left, at which point the person with the most stones wins. ...
Freedom Trail Problem Problem In the video game Fallout 4, the quest “Road to Freedom” requires players to reach a metal dial called the “Freedom Trail Ring” and use the dial to spell a specific keyword to open the door. Given a string ring that represents the code engraved on the outer ring and another string key that represents the keyword that needs to be spelled, return the minimum number of steps to spell all the characters in the keyword. ...