Home / Topics / #hash-table

#Hash Table

20 posts

May 112021

Leetcode - Count Good Meals Solution

A good meal is a meal that contains exactly two different food items with a sum of deliciousness equal to a power of two. You can pick any two different foods to make a good meal. Given an array of integers…

leetcode array Hash Table2 min read

May 112021

Leetcode - Number of Good Pairs Solution

Given an array of integers nums. A pair (i,j) is called good if nums[i] == nums[j] and i < j. Return the number of good pairs. Example 1: Example 2: Example 3: Constraints: 1 <= nums.length <= 100 1 <= nums[i] <= 100…

leetcode array Hash Table1 min read

May 112021

Leetcode - Making File Names Unique Solution

Given an array of strings names of size n. You will create n folders in your file system such that, at the ith minute, you will create a folder with the name names[i]. Since two files cannot have the same name, if you…

leetcode string Hash Table3 min read

May 112021

Leetcode - Display Table of Food Orders in a Restaurant Solution

Given the array orders, which represents the orders that customers have done in a restaurant. More specifically orders[i]=[customerNamei,tableNumberi,foodItemi] where customerNamei is the name of the customer…

leetcode Hash Table3 min read

May 062021

Leetcode - How Many Numbers Are Smaller Than the Current Number Solution

Given the array nums, for each nums[i] find out how many numbers in the array are smaller than it. That is, for each nums[i] you have to count the number of valid j's such that j != i and nums[j] < nums[i]. Return the…

leetcode array Hash Table2 min read

May 032021

Leetcode - Alphabet Board Path Solution

On an alphabet board, we start at position (0, 0), corresponding to character board[0][0]. Here, board = ["abcde", "fghij", "klmno", "pqrst", "uvwxy", "z"], as shown in the diagram below. We may make the following…

leetcode Hash Table string1 min read

May 022021

Leetcode - N-Repeated Element in Size 2N Array Solution

In a array A of size 2N, there are N+1 unique elements, and exactly one of these elements is repeated N times. Return the element repeated N times. Example 1: Example 2: Example 3: Note: 4 <= A.length <= 10000 0 <= A[i]…

leetcode Hash Table1 min read

May 012021

Leetcode - Jewels and Stones Solution

You're given strings jewels representing the types of stones that are jewels, and stones representing the stones you have. Each character in stones is a type of stone you have. You want to know how many of the stones…

leetcode Hash Table1 min read

May 012021

Leetcode - Daily Temperatures Solution

Given a list of daily temperatures T, return a list such that, for each day in the input, tells you how many days you would have to wait until a warmer temperature. If there is no future day for which this is possible…

leetcode Hash Table stack1 min read

Apr 242021

Leetcode - Find All Anagrams in a String Solution

Given two strings s and p, return an array of all the start indices of p's anagrams in s. You may return the answer in any order. Example 1: Example 2: Constraints: 1 <= s.length, p.length <= 3 * 104 s and p consist of…

leetcode Hash Table1 min read

Apr 242021

Leetcode - First Unique Character in a String Solution

Given a string s, return the first non-repeating character in it and return its index. If it does not exist, return -1. Example 1: Example 2: Example 3: Constraints: 1 <= s.length <= 105 s consists of only lowercase…

leetcode Hash Table string1 min read

Apr 242021

Leetcode - Design Twitter Solution

Design a simplified version of Twitter where users can post tweets, follow/unfollow another user, and is able to see the 10 most recent tweets in the user's news feed. Implement the Twitter class: Twitter() Initializes…

leetcode Hash Table heap4 min read

Apr 242021

Leetcode - Top K Frequent Elements Solution

Given an integer array nums and an integer k, return the k most frequent elements. You may return the answer in any order. Example 1: Example 2: Constraints: 1 <= nums.length <= 105 k is in the range [1, the number of…

leetcode Hash Table heap1 min read

Mar 222021

Leetcode - Bulls and Cows Solution

You are playing the Bulls and Cows game with your friend. You write down a secret number and ask your friend to guess what the number is. When your friend makes a guess, you provide a hint with the following info: The…

leetcode Hash Table2 min read

Mar 222021

Leetcode - Word Pattern Solution

Given a pattern and a string s, find if s follows the same pattern. Here follow means a full match, such that there is a bijection between a letter in pattern and a non-empty word in s. Example 1: Example 2: Example 3…

leetcode Hash Table1 min read

Mar 202021

Leetcode - Contains Duplicate II 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. Example 1: Example 2: Example 3: Constraints: 1 <=…

leetcode array Hash Table1 min read

Mar 202021

Leetcode - Happy Number Solution

Write an algorithm to determine if a number n is happy. 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…

leetcode Hash Table Math1 min read

Mar 202021

Leetcode - Single Number Solution

Given a non-empty array of integers nums, every element appears twice except for one. Find that single one. Follow up: Could you implement a solution with a linear runtime complexity and without using extra memory?…

leetcode Hash Table Bit Manipulation1 min read

Mar 202021

Leetcode - Group Anagrams Solution

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…

leetcode Hash Table string1 min read

Mar 202021

Leetcode - Valid Sudoku Solution

Determine if a 9 x 9 Sudoku board is valid. Only the filled cells need to be validated according to the following rules: Each row must contain the digits 1-9 without repetition. Each column must contain the digits 1-9…

leetcode Hash Table2 min read