Algorithms and Data Structures

Implement pow(x, n), which calculates x raised to the power n (i.e., xn). Solution C# Python3

Implement pow(x, n), which calculates x raised to the power n (i.e., xn). Solution C# Python3

Given an array of integers nums and an integer k, return the total number of subarrays whose sum equals to k. A subarray is a contiguous non-empty sequence of elements within an array. Solution C# Python3

Given a string s, find the first non-repeating character in it and return its index. If it does not exist, return -1. Solution C# Python3

Every valid email consists of a local name and a domain name, separated by the ‘@’ sign. Besides lowercase letters, the email may contain one or more ‘.’ or ‘+’. For example, in “alice@leetcode.com”, “alice” is the local name, and “leetcode.com” is the domain name. If you add periods ‘.’ between some characters in the local name part of an email address, mail sent there will be forwarded to the same address without dots in the … Read more

Given an array of strings strs, group the anagrams together. You can return the answer in any order. An Anagram is a word or phrase formed by rearranging the letters of a different word or phrase, typically using all the original letters exactly once. Solution C# Python3

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. You can return the answer in any order. Solution C# Python3

You are given two integer arrays nums1 and nums2 sorted in ascending order and an integer k. Define a pair (u, v) which consists of one element from the first array and one element from the second array. Return the k pairs (u1, v1), (u2, v2), …, (uk, vk) with the smallest sums. Solution C# Python3

Design a class to find the kth largest element in a stream. Note that it is the kth largest element in the sorted order, not the kth distinct element. Implement KthLargest class: KthLargest(int k, int[] nums) Initializes the object with the integer k and the stream of integers nums.int add(int val) Appends the integer val to the stream and returns the element representing the kth largest element in the stream. Solution Python3

Given the head of a singly linked list, reverse the list, and return the reversed list. Solution C# Python3