Note: All the quadruples should be internally sorted, i. LeetCode Solutions in C++23, Java, Python, MySQL, and TypeScript. * nums [a] + nums [b] + nums [c] + nums [d] == target You may return the answer in any order. In short, you need to return an array of all the unique quadruplets [arr [a], Jan 9, 2026 · Solution For A two digit number is 3 more than 4 times the sum of its digits. This problem can be solved using multiple techniques and algori Jul 31, 2024 · Leetcode 4Sum problem solution in python, java, c++ and c programming with practical program code example and complete full explanation The solution set must not contain duplicate quadruplets. Sep 14, 2025 · 4-sum problem: Given an unsorted integer array, check if it contains four elements tuple (quadruplets) having a given sum. Feb 6, 2013 · The 4-SUM is as follows: Given an array of N distinct integers find 4 integers a, b, c, d such that a+b+c+d = 0. The problem statement from leetcode says: Given an array S of n integers, are there elements a, b, c, and d in S such that a + b + c + d = target? Find all unique Dec 23, 2022 · 4Sum. The solution utilizes a hashmap-based approach to efficiently count combinations of sums in two divided half segments of the combined arrays. The main functionality is handled by the findQuadruplets function which heavily utilizes the helper function findKSum to facilitate the process of finding ( k )-sum combinations. 2. org/plus/dsa/pro Contribute to stattrak-dragonlore/leetcode-solutions development by creating an account on GitHub. We are going to extend the ideas here to find all distinct Quadruplets. 4Sum Given an array nums of n integers and an integer target, are there elements a, b, c, and d in nums such that a + b + c + d = target? Find all unique quadruplets in the array which gives the sum of target. 4Sum problem of Leetcode. In this problem, you must find all unique quadruplets in an array that sum up to a specific target value. length < 4) return []; In this article, we have explored an insightful approach/ algorithm to find the 4 elements in an array whose sum is equal to the required answer (4 Sum problem). If 18 is added to this number, the sum is equal to the number obtained by interchanging the digits. Better than official and forum solutions. Checkout the problem link 👇🏼 4 Sum | Brute - Better - Optimal with Codes https://takeuforward. Can you solve this real interview question? 4Sum II - Given four integer arrays nums1, nums2, nums3, and nums4 all of length n, return the number of tuples (i, j, k Given an array nums of n integers and an integer target, are there elements a, b, c, and d in nums such that a + b + c + d = target? Find all unique quadrupl The brute force approach to solving the 4Sum problem involves systematically checking every combination of four numbers in the array. Apr 13, 2024 · In this series, both the three and four sum solutions rely on the two sum strategy to arrive at a solution. We explore various approaches to find all unique quadruplets in an array that sum to a given target. Rather than checking every possible pair, we store each number in an unordered set during iterating over the array's elements. Understanding the 4Sum Problem The 4Sum problem challenges you to find all unique quadruplets in an array that sum to a specific target. 4 Sum - Given an array S of n integers, are there elements a, b, c, and d in S such that a + b + c + d = target? Find all unique quadruplets in the array which gives Can you solve this real interview question? 4Sum II - Given four integer arrays nums1, nums2, nums3, and nums4 all of length n, return the number of tuples (i, j, k Mar 12, 2025 · In competitive programming, solving the 4Sum problem efficiently is a classic challenge that tests your understanding of algorithms and data structures. Unlike the simpler 2Sum and 3Sum problems, this version requires considering four elements, making efficiency and duplicate handling critical. This problem 18. Initially P does not know the solution, since 52 = 4 × 13 = 2 × 26 and S knows that P does not know the solution since all the possible sums to 17 within the constraints produce similarly ambiguous products. Find all the unique set of 4 elements in array such that sum of those 4 elements is equal to the given integer x. Have a hassle free one stop solution for up-skilling and preparing. class Solution { public: vector<vector<int>> fourSum(vector<int>& nums, int target) { In this post, we are going to solve the 18. The key is to reduce the time complexity from O (n⁴) using nested loops to a more optimal combination of sorting Click here 👆 to get an answer to your question ️ |x-2|+|x+4|=10 Find sum of all x 6 days ago · Advanced version of 2Sum & 3Sum 💯#LeetCode #4Sum #DSA #Shorts Jan 9, 2026 · Stuck on the question or explanation? Connect with our 413 tutors online and get step by step solution of this question. Can you solve this real interview question? 4Sum - Given an array nums of n integers, return an array of all the unique quadruplets [nums [a], nums [b], nums [c], nums [d]] such that: * 0 <= a, b, c, d < n * a, b, c, and d are distinct. Solution For Compute the sum of four-digit numbers formed with the our digits 2,5,3,8 if each digit is used only once in each arrangement. 4Sum. Dec 27, 2022 · 4Sum - LeetCode 18 - LeetCode Python - Two PointersHello guys,In this video, i will show you how to solve the Problem 4 SUM using the two pointers techniques Sep 10, 2020 · Two approaches to solving the Two Sum problem on Leetcode. It’s a common problem in algorithmic challenges and is used to test understanding of array manipulation, sorting, and optimization techniques. Therefore, we can first sort the array, which makes it easy to skip duplicate elements. com/neetcode1🐮 S class Solution { public: vector<vector<int>> fourSum (vector<int>& nums, int target) { 1. However once P knows that S believes there are multiple possible solutions Given an array arr[] of integers and another integer target. If the investment was for 5 years, the interest earned would have been 375 more. For each number, we calculate its complement (i. You have to find all unique quadruples from the given array whose sum is equal to the given target. 5% simple interest per annum for 4 years. This concept finds many uses in computational geometry. 4Sum in Python, Java, C++ and more. Problem Given an array S of n integers, are there elements a, b, c, and d in S such that a + b + c + d = target? Find all unique quadruplets in the array which gives the sum of target. . For N = 1 to 5: SUM = SUM + (N * 3) % 4. Jan 12, 2026 · Solution For A sum of money was invested at the rate of 7. 4Sum - Given an integer x and an array. If the difference between seven times and three times a number is 48, what will be the number? On adding 8 to the three times a whole number gives 31. io/ - A better way to prepare for Coding Interviews🥷 Discord: https://discord. This video explains a very important programming interview problem which is the 4 sum problem. Jan 10, 2026 · Solution For If the square of sum of three positive consecutive natural numbers exceeds the sum of their squares by 292, then what is the largest of the three numbers? Can you solve this real interview question? 4Sum - Given an array nums of n integers, return an array of all the unique quadruplets [nums [a], nums [b], nums [c], nums [d]] such that: * 0 <= a, b, c, d < n * a, b, c, and d are distinct. 4Sum is a Leetcode medium level problem. If you'd like to share your solution for feedback and ideas, please head to the solutions tab and post it there. Discover optimization strategies, time complexity analysis, and practical implementation tips for this classic coding interview problem. Solutions in Python, Java, C++, JavaScript, and C#. What is SUM? Jul 26, 2025 · Hashing provides a more efficient solution to the 2-Sum problem. The solution has X and Y as 4 and 13, with P initially knowing the product is 52 and S knowing the sum is 17. Mar 8, 2022 · 🚀 https://neetcode. Detailed solution explanation for LeetCode problem 18: 4Sum. , target - current number) and check if this complement exists in the set. The following code implements this simple method using four nested loops. So there's the obvious n^3 solution with sorting, two nested for loops and then checking. Note: The solution set must not contain duplicate quadruplets. Nov 27, 2023 · Understand the different ways to solve the 4 Sum problem using naive approach and 4 pointer method with examples in C++, Python and Java. Feel free to drop any questions on the video below, along with any other questions you'd like to se 📊 4 Sum Problem - LeetCode 18 | Optimal Solution with Explanation In this video, I will explain the 4 Sum Problem from LeetCode (Problem #18), which is a very popular Data Structures and Can you solve this real interview question? 4Sum II - Given four integer arrays nums1, nums2, nums3, and nums4 all of length n, return the number of tuples (i, j, k May 13, 2025 · The given Java code presents a method to solve the "4Sum II" problem, which involves finding tuples from four separate arrays (A, B, C, D) such that their sum totals to zero. This guide provides clear explanations, examples, and code snippets. class Solution { public: vector<vector<int>> fourSum(vector<int>& nums, int target) { #19 Leetcode Remove Nth Node From End of List Solution in C, C++, Java, JavaScript, Python, C# Leetcode Try With Live Editor Category - Leetcode Online Judge Maniruzzaman Akash 2 years ago 1280 0 Ex: #1 #1 Leetcode - Two sum problem solution in JavaScript, C , Java, Python, C# and C++ programming leetcode Beginner LintCode炼码题解 / 四数之和 · 4Sum 四数之和 · 4Sum 模拟法相向双指针排序算法排序双指针哈希表两根指针数组 hash table sort Dec 9, 2024 · Master the 4Sum algorithm: Learn how to efficiently find unique quadruplets that sum to a target value using the Two-Pointer technique. Jan 9, 2026 · Solution For A flowchart sets SUM = 0. Jan 2, 2026 · The solution of the equation 5x + 4 = 28 is 24/5 (True/False) What will be the solution of equation 8 - 4x = 3? Find the solution of the equation 3y/2 + 7 = 12 + 2y/3. In this article, we dive deep into the 4Sum problem, discuss various approaches, analyze their complexities, and present a well-optimized solution using the two-pointer technique. Aug 13, 2025 · We have discussed how to find if a quadruple with given sum exists or not in an array. Please don't post any solutions in this discussion. Find the possible number of ways of arrangin Detailed solution for 4 Sum | Find Quads that add up to a target value - Problem Statement: Given an array of N integers, your task is to find unique quads that add up to give a target value. A solution set is: [ [-1, 0, 0, 1], [-2, -1, 1, 2], [-2, 0, 0, 2] ] Solution /** * @param {number[]} nums * @param {number} target * @return {number[][]} */ var fourSum = function(nums, target) { if (nums. Example: Sep 8, 2018 · Find all unique quadruplets in the array which gives the sum of target. The problem discussion is for asking questions about the problem or for sharing tips - anything except for solutions. The goal is to identify all unique quadruplets that sum up to the target value. e for any quadruple [q1, q2, q3, class Solution { public: vector<vector<int>> fourSum (vector<int>& nums, int target) { Learn to efficiently solve the 4 sum problem with expert strategies and practical tips to tackle this common coding interview challenge. 4Sum II in Python, Java, C++ and more. 3. Next, we enumerate the first two elements of the quadruplet, nums[i] n u m s [i] and nums[j] n u m s [j], where i <j i <j. But is there a way to do better? Note this isn't the decision problem, just see if a solution exists but instead to return all unique quadruplets. I walk through the code step-by-step, explaining the logic behind eac 18. Day 61 of 100 👍 #100DaysOfDSA Problem : 4Sum Given an integer array nums containing n elements and an integer target, the task is to find and return all unique quadruplets of numbers from the May 12, 2025 · This solution is ideally designed to find all unique quadruples in an array that sum up to a target value. Nov 11, 2024 · Learn how to find all quadruplets in an array that sum to a specific target. This article delves into the Four Sum problem, a classic challenge in computer science and algorithm design. Example: Given array nums = [1, 0, -1, 0, -2, 2], and target = 0. The two-pointer technique from 2Sum and 3Sum extends naturally to 4Sum. We can therefore infer that the two sum solution is known if k = 2 hence forming the In-depth solution and explanation for LeetCode 454. 🏋️ Python / Modern C++ Solutions of All 3792 LeetCode Problems (Weekly Update) - kamyu104/LeetCode-Solutions In this video, I solve the LeetCode 4Sum problem (Medium) using a brute force approach. Follow our clear and concise explanation to understand the approach and code for Nov 14, 2025 · Try it on GfG Practice [Naive Solution] Using Four Nested Loop - O (n^4) Time and O (1) Space: Generate all possible quadruples and compare the sum of every quadruple with target. I could come up with a cubic algorithm using LeetCode Solutions in C++23, Java, Python, MySQL, and TypeScript. After sorting, we fix the first two elements with nested loops, then use two pointers to find pairs that complete the target sum. Let's see code, 18. Jul 23, 2025 · The 4Sum problem is an extension of the well-known 2-Sum and 3-Sum problems, where the goal is to find four numbers in an array that sum up to a given target. e. gg/ddjKRXPqtk🐦 Twitter: https://twitter. Intuitions, example walk through, and complexity analysis. In-depth solution and explanation for LeetCode 18. Dec 18, 2015 · Solutions Solution 1: Sorting + Double Pointers We notice that the problem requires us to find non-repeating quadruplets.

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4sum Solution. Note: All the quadruples should be internally sorted, i. LeetCode