Climbing Stairs LeetCode Solution
You are climbing a staircase. It takes n steps to reach the top. Each time you can either climb 1 or 2 steps. In how many distinct ways can you climb to the top?
Easy
Reverse Linked List LeetCode Solution
Given the head of a singly linked list, reverse the list, and return the reversed list.
Add Digits LeetCode Solution
Given an integer num, repeatedly add all its digits until the result has only one digit, and return it.
Nim Game LeetCode Solution
Given n, the number of stones in the heap, return true if you can win the game assuming both you and your friend play optimally, otherwise return false.
Valid Parentheses LeetCode Solution
Given a string s containing just the characters ‘(‘, ‘)’, ‘{‘, ‘}’, ‘[‘ and ‘]’, determine if the input string is valid.
Single Number LeetCode Solution
Given a non-empty array of integers nums, every element appears twice except for one. Find that single one.
Intersection of Two Linked Lists LeetCode Solution
Given the heads of two singly linked-lists headA and headB, return the node at which the two lists intersect. If the two linked lists have no intersection at all, return null.
Reverse Bits LeetCode Solution
Reverse bits of a given 32 bits unsigned integer.
Happy Number LeetCode Solution
Write an algorithm to determine if a number n is happy. Return true if n is a happy number, and false if not.
Contains Duplicate II LeetCode Solution
Given an integer array nums and an integer k, return true if there are two distinct indices i and j in the array such that nums[i] == nums[j] and abs(i – j) <= k.
Majority Element LeetCode Solution
Given an array nums of size n, return the majority element. The majority element is the element that appears more than [n / 2] times. You may assume that the majority element always exists in the array.
Contains Duplicate LeetCode Solution
Given an integer array nums, return true if any value appears at least twice in the array, and return false if every element is distinct.
Two Sum LeetCode Solution
Given an array of integers nums and an integer target, return indices of the two numbers such that they add up to target. You may assume that each input would have exactly one solution, and you may not use the same element twice.
Remove Duplicates from Sorted Array LeetCode Solution
Given an integer array nums sorted in non-decreasing order, remove the duplicates in-place such that each unique element appears only once. The relative order of the elements should be kept the same.