Happy Number
A happy number is a number defined by the following process: Starting with any positive integer, replace the number by the sum of the squares of its digits. Repeat the…
Coding Patterns
Linked List Cycle II
Given a linked list, determine if it contains a cycle. If a cycle is present, find the node where the cycle begins and return it. If there is no cycle,…
Linked List Cycle
Given a linked list, determine if it has a cycle in it. A cycle is when a node in the linked list points to a previously visited node, forming a…
Reverse Nodes in k-Group
Given the head of a singly linked list and an integer k, reverse the nodes of the list k at a time and return the new head of the reversed…
Reverse Linked List II
Given the head of a singly linked list and two integers left and right, reverse the nodes of the list from position left to position right, and return the new…
Rotate List
Given the head of a singly linked list and an integer k, rotate the linked list to the right by k places. The rotation means moving the last k nodes…
Reverse Linked List
Given the head of a singly linked list, reverse the list in-place and return the new head of the reversed linked list.
Meeting Scheduler
You are given the availability of two people's schedules, represented as lists of intervals . Each interval represents the available time for each person, and it is a closed interval…
Meeting Rooms II
Given a list of meeting intervals, represented as pairs of integers , where start denotes the start time of the meeting and end denotes the end time of the meeting,…
Meeting Rooms
Given a list of meeting intervals, represented as pairs of integers , where start denotes the start time of the meeting and end denotes the end time of the meeting,…