Hashing

A collection of 54 posts

Hashing

Redistribute Characters to Make All Strings Equal Solution In C++/Java/Python/JS

Problem Description You are given an array of strings words (0-indexed). In one operation, pick two distinct indices i and j, where words[i] is a non-empty string, and move any character from words[i] to any position in words[j]. Return true if you can make every string in

Hashing

Count Pairs That Form a Complete Day II Solution In C++/Java/Python/JS

Problem Description Given an integer array hours representing times in hours, return an integer denoting the number of pairs i, j where i < j and hours[i] + hours[j] forms a complete day. A complete day is defined as a time duration that is an exact multiple of 24

Number of Submatrices That Sum to Target Solution In C++/Java/Python/JS

Problem Description Given a matrix and a target, return the number of non-empty submatrices that sum to target. What is a Submatrix? A submatrix x1, y1, x2, y2 is the set of all cells matrix[x][y] with x1 <= x <= x2 and y1 <= y <= y2. Two

Hashing

Count the Number of Beautiful Subarrays Solution In C++/Java/Python/JS

Problem Description You are given a 0-indexed integer array nums. In one operation, you can: Choose two different indices i and j such that 0 <= i, j < nums.length. Choose a non-negative integer k such that the kth bit (0-indexed) in the binary representation of nums[i] and

Number of Wonderful Substrings Solution In C++/Java/Python/JS

Problem Description A wonderful string is a string where at most one letter appears an odd number of times. For example, "ccjjc" and "abab" are wonderful, but "ab" is not. Given a string word that consists of the first ten lowercase English letters ('

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Binary Subarrays With Sum Solutions in C++/Java/Python/JS

Problem Description We are given a binary array nums containing only 0s and 1s) and an integer goal. The task is to return the number of non-empty contiguous subarrays whose elements sum up exactly to goal. What is a Subarray? A subarray is a contiguous part of the array, meaning

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Sum of Digit Differences of All Pairs Solution In C++/Java/Python/JS

Problem Description Given an array nums consisting of positive integers where all integers have the same number of digits. The digit difference between two integers is the count of different digits that are in the same position in the two integers. Return the sum of the digit differences between all

Minimum Seconds to Equalize a Circular Array Solution In C++/Java/Python/JS

Problem Description There are two mice and n different types of cheese, each type of cheese should be eaten by exactly one mouse. A point of the cheese with index i (0-indexed) is: reward1[i] if the first mouse eats it. reward2[i] if the second mouse eats it. You

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Maximum Size of a Set After Removals Solution In C++/Java/Python/JS

Problem Description You are given two 0-indexed integer arrays nums1 and nums2 of even length n. You must remove n / 2 elements from nums1 and n / 2 elements from nums2. After the removals, you insert the remaining elements of nums1 and nums2 into a set s. Return the maximum possible

Card Flipping Game Solution In C++/Java/Python/JS

Problem Description You are given two 0-indexed integer arrays fronts and backs of length n, where the ith card has the positive integer fronts[i] printed on the front and backs[i]  printed on the back. Initially, each card is placed on a table such that the front number is

Vowel Spellchecker Solution In C++/Java/Python/JS

Problem Description Given a wordlist, we want to implement a spellchecker that converts a query word into a correct word. For a given query word, the spell checker handles two categories of spelling mistakes: Capitalization: If the query matches a word in the wordlist (case-insensitive), then the query word is

Alphabet Board Path Solution In C++/Java/Python/JS

Problem Description On an alphabet board, we start at position (0, 0), corresponding to character board[0][0]. Here, board = ["abcde", "fghij", "klmno", "pqrst", "uvwxy", "z"]. We may make the following moves: 'U' moves our position

Pairs of Songs With Total Durations Divisible by 60 Solution In C++/Java/Python/JS

Problem Description You are given a list of songs where the ith song has a duration of time[i] seconds. Return the number of pairs of songs for which their total duration in seconds is divisible by 60. Formally, we want the number of indices i, j such that i

Brick Wall Solution In C++/Java/Python/JS

Problem Description There is a rectangular brick wall in front of you with n rows of bricks. The ith row has some number of bricks each of the same height (i.e., one unit) but they can be of different widths. The total width of each row is the same.

Sort Characters By Frequency Solution In C++/Java/Python/Javascript

Problem Description Given a string s, sort it in decreasing order based on the frequency of the characters. The frequency of a character is the number of times it appears in the string. Return the sorted string. If there are multiple answers, return any of them. Example Input: s = "

Minimum Number of Operations to Make Word K-Periodic Solution In C++/Java/Python/Javascript

Problem Description You are given a string word of size n and an integer k such that k divides n. In one operation, you can pick any two indices i and j that are divisible by k, then replace the substring of length k starting at i with the substring

Can Convert String in K Moves Solution In C++/Java/Python/Javascript

Problem Description Given two strings s and t, your goal is to convert s into t in k moves or less. During the ith (1 <= i <= k) move you can: 1) Choose any index j (1-indexed) from s, such that 1 <= j <= s.length and j

Restore the Array From Adjacent Pairs Solution In C++/Java/Python/Javascript

Problem Description There is an integer array nums that consists of n unique elements, but you have forgotten it. However, you do remember every pair of adjacent elements in nums. You are given a 2D integer array adjacentPairs of size n - 1 where each adjacentPairs[i] = [ui, vi] indicates

Tuple with Same Product Solution In C++/Java/Python/Javascript

Problem Description Given an array nums of distinct positive integers, return the number of tuples (a, b, c, d) such that a * b = c * d where a, b, c, and d are elements of nums, and a != b != c != d. Problem Explanation what is tuple? A group of immutable elements

Split the Array to Make Coprime Products Solution In C++/Java/Python/Javascript

Problem Description You are given a 0-indexed integer array nums of length n. A split at an index i where 0 <= i <= n - 2 is called valid if the product of the first i + 1 elements and the product of the remaining elements are coprime. For example,

4Sum II Solution In C++/Java/Python/Javascript

Problem Description Given four integer arrays nums1, nums2, nums3, and nums4 all of length n, return the number of tuples (i, j, k, l) such that: 0 <= i, j, k, l < n nums1[i] + nums2[j] + nums3[k] + nums4[l] == 0 Examples: Input : nums1 = [1,2], nums2 = [-2,

Count Artifacts That Can Be Extracted Solution In C++/Java/Python/Javascript

Problem Description There is an n x n 0-indexed grid with some artifacts buried in it. You are given the integer n and a 0-indexed 2D integer array artifacts describing the positions of the rectangular artifacts where artifacts[i] = [r1i, c1i,r2i, c2i] denotes that the ith artifact is buried

Replace Elements in an Array Solution In C++/Java/Python/Javascript

Problem Description You have given a 0-indexed array nums that consists of n distinct positive integers. Apply m operations to this array, where in the ith operation you need to replace the number operations[i][0] with operations[i][1].' It is guaranteed that in the ith operation: 1.

Find Words That Can Be Formed by Characters Solution In C++/Java/Python/Javascript

Problem Description We are given a list of words and a string of characters chars. A word is considered good if all its characters can be made using the characters in the given string, and each character in the string can only be used once. Your task is to find

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Integer to Roman Solution In C++/Java/Python/Javascript

Problem Description We are given the task to convert an integer to its equivalent Roman numeral representation. Roman numerals use a specific set of symbols that correspond to certain values. The seven symbols used are I, V, X, L, C, D, and M. Here's their corresponding values: I