Questions tagged [dynamic-programming]

Dynamic programming is an algorithmic technique for efficiently solving problems with a recursive structure containing many overlapping subproblems.

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Calculate sum of a substring

I try to solve some old Codeforces questions. The problem is; Petya once wrote a sad love song and shared it to Vasya. The song is a string consisting of lowercase English letters. Vasya made up q ...
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117 views

Killing a Hydra - Overengineered

Background This question is inspired by the question: Killing a hydra, and my response therein. I will restate the problem at hand in full so that this question is fully self contained You can only ...
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1answer
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K Inverse Pairs Array - Brute Force

For an integer array nums, an inverse pair is a pair of integers [i, j] where ...
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1answer
57 views

Haskell implementation of Needleman-Wunsch

The code below is a Haskell implementation of Needleman-Wunsch algorithm for sequence alignment (and string edit distance). It's an experiment in trying to closely imitate the dynamic programming ...
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I want reduce the time complexity for this ladder problem to find the minimum ladders required

I was trying to attempt below given challenge. I tried multiple ways to solve the problem but none of them were good enough to pass the time limit. Please advise if you have any idea to improve on ...
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Unique Paths II, dynamic programming problem, O(n^2) time, O(n^2) space

This is based on this leetcode question. I get the correct answer, but I know it could be much, much cleaner. I also know there is supposed to be an O(n) space solution, but I'm not sure how to ...
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1answer
389 views

Count the number of distinct subarrays

I want to determine the number of distinct subarrays that can form having at most a given number of odd elements. Two subarrays are distinct if they differ at even one position. The subarray is a ...
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1answer
53 views

Haskell Dynamic Programming on a Tree

Here is my shot at Homework 8 of CIS-194 (from Spring '13). The problem is about a hierarchy of employees at a company (a tree), each node being of type Employee, ...
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Efficiently calculate value of Pascal's Triangle using memoization and recursion(updated)

Follow up to Efficiently calculate value of Pascal's Triangle using memoization and recursion Based on feedback given by jvwh in the answers ...
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1answer
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Efficiently calculate value of Pascal's Triangle using memoization and recursion

So reading about functional programming, applications to dynamic programming, and learning Scala. I figured I would try it out with a popular example, Pascal's Triangle, tests against known values ...
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LeetCode: Delete and Earn C#

https://leetcode.com/problems/delete-and-earn/ Given an array nums of integers, you can perform operations on the array. In each operation, you pick any nums[i] and delete it to earn nums[i] points. ...
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LeetCode: range sum query mutable c#

https://leetcode.com/problems/range-sum-query-mutable/ I am trying to solve this question using dynamic programming. I guess the guys in leetcode want to limit us to use segment tree or one of the ...
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Grid Dynamic Programming

atcoder.jp Problem Statement: There is a grid with H horizontal rows and W vertical columns. Let (i,j) denote the square at the ...
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1answer
132 views

Searching for an idiomatic Rust implementation of Minimum Edit Distance (LeetCode #72)

I am solving LeetCode Dynamic Programming challenges (this one is #72, at https://leetcode.com/problems/edit-distance). Here below, I've implemented a Rust solution for the minimum edit distance ...
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1answer
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Find a sum using just two different digits

The problem statement was pretty easy and I was able to run half of the test cases, but some of the test cases in the end gave me the error of memory limit reached. What can I do here to improve the ...
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Divide a set into subset with some constraints

Note - I am not sure whether this question belongs to stackoverflow or CSE stackexchange or here Problem: Given a list Lconsisting of not necessarily unique non-...
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C++ - Longest Common Subsequence

Link to the Problem Here is my code to compute the length of the longest common subsequence of two integer arrays arr[] and brr[]...
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161 views

LeetCode: Stone Game C#

https://leetcode.com/problems/stone-game/ Alex and Lee play a game with piles of stones. There are an even number of piles arranged in a row, and each pile has a positive integer number of stones ...
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Code A Primitive Calculator ( x3,x2,+1) Using Dynamic programming [closed]

Question -You are given a primitive calculator that can perform the following three operations with the current number 𝑥: multiply 𝑥 by 2, multiply 𝑥 by 3, or add 1 to 𝑥. Your goal is given ...
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Generate unique string permutations recursively

🧩 Objective Write a recursive method for generating all permutations of an input string. Return them as a set. See: Recursive String Permutations - Interview Cake 🔎 Questions 1: How does the ...
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LeetCode on Longest Palindromic Substring in Python

This is a programming question from LeetCode: Given a string s, return the longest palindromic substring in s. Example 1: Input: s = "babad" Output: "bab" Note: "aba" is ...
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1answer
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Why below recursive DP solution is so slow? (Leetcode Q# 123 - Best Time to Buy and Sell Stock III)

This is regarding leetcode Question# 123. I have solved the question (code below) but the solution is showing "Your runtime beats 5.89 % of cpp submissions."? Is there any additional ...
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Split money into every possible combination of coin denominations

Background and objective of the code Based on this Dev.to challenge, I wrote the Python code below (TIO link also available). The task was to return the least number of coins in a given denomination ...
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1answer
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C++ Dynamic Array Class Testing

I'm creating a basic Dynamic Array class in C++, and I'd like to know if there are any bugs/memory leaks I haven't noticed yet. dyn_arr.h : ...
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1answer
55 views

Find sequence to a target number using restricted set of primitive operations

Given an integer 𝑛, compute the minimum number of operations(+1, x2, x3) needed to obtain the number 𝑛 starting from the number 1. I did this using this code: ...
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2answers
105 views

Knapsack performance issue

I'm solving a knapsack problem here. It works, but gives time limit exceeds on a certain test case. Problem statement There are N items, numbered 1,2,…,N. For each i (1≤i≤N), Item i has a weight of ...
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220 views

LeetCode 1320: Minimum Distance to Type a Word Using Two Fingers II

I'm posting my Python code for LeetCode's 1320. If you have time and would like to review, please do so. Problem You have a keyboard layout as shown above in the XY plane, where each English ...
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1answer
80 views

LeetCode 1320: Minimum Distance to Type a Word Using Two Fingers I

I'm posting my C++ code for LeetCode's 1320. If you have time and would like to review, please do so. Thank you! Problem You have a keyboard layout as shown above in the XY plane, where each English ...
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1answer
168 views

LeetCode 375: Guess Number Higher or Lower II

I'm posting my C++ code for LeetCode's Guess Number Higher or Lower II. If you have time and would like to review, please do so. Problem We are playing the Guess Game. The game is as follows: I pick ...
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1answer
206 views

How can I use the State monad effectively in Haskell?

I have written a simple fibonacci function in Haskell that uses the State monad to save solutions to overlapping sub-problems. Now despite the function working I am not really happy with the solution, ...
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1answer
240 views

Maximum subset sum with no adjacent elements

Write a function that takes an array of integers (Both Positive and negative) and return the maximum sum of non adjacent elements. Note that even if all values are negative, I don't have an option to ...
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2answers
86 views

Recursive brute-force approach to maximum points you can obtain from cards

I came across this question on Leetcode. The question description is as follows: There are several cards arranged in a row, and each card has an associated number of points. The points are given in ...
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67 views

(Java) Read .txt and organize activities for hours / minutes

Doubts in logic to generate the output file according to the example I need that even if he reaches the total_min <720 condition he continues to travel the lines. 720 is the total number of minutes ...
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1answer
59 views

Matrix problem, the path that is the flattest

So in this problem I am given an NxN matrix, in which each value of the matrix represents an altitude. I need to find the best path from the top-left corner to the bottom-right one, my moves being ...
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1answer
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LeetCode: Trapping Rain Water DP C#

Please review for performance and C# style. I already solved this question in 1 way. LeetCode: trapping rain water C# I tried also the dynamic programming approch https://leetcode.com/problems/...
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C# - Reapply the manipulation of JS Object in .Net Core

IMPORTANT: I made another version with some improvements: Version 2 Since some months ago I disagree with the native/code methods to manipulate dynamic or ...
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1answer
67 views

Is there a route to the end of the jump table?

I'm currently learning about Dynamic Programming and solving a "coding question" related to the topic. Given an array of non-negative integers, you are initially positioned at the first ...
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1k views

LeetCode: Longest String Chain (Java)

For the question, I had a pretty messy solution so I would like some advice on how to better use Java to make the code a bit cleaner. Also, a semi-hack that I did that I'm not proud of is checking if ...
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1answer
46 views

Dynamic SQL query for count data

I'm working on an application that counts the number of employees in each department. Here's my code: ...
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1answer
103 views

Find the smallest number of perfect squares that sum to a target

Given a positive integer n, find the smallest number of perfect squares (for example, 1, 4, 9, 16, ...) that sum to n. ...
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2answers
88 views

A function to scan user input as string

I know that multiple functions are already available. However, I thought of writing my own because I wanted to learn the logic (and also because I thought there wasn't enough confusion :P). Please ...
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1answer
656 views

Printing the number of ways a message can be decoded

My below solution to the following problem is exceeding the maximum recursion depth. I am looking for any improvements which i can make. Problem Alice and Bob need to send secret messages to each ...
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1answer
400 views

Maximum sum combination

I am trying to solve this question: https://www.codechef.com/problems/TADELIVE Andy and Bob are the only two delivery men of Pizza-chef store. Today, the store received N orders. It's known that ...
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1answer
247 views

Total number of non overlapping subsets

I am trying to solve this question. The essence of the problem is this: Given a list of school classes with start and end times, find the total number of non-overlapping subsets. I've written up a ...
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3answers
908 views

Minimum path sum in a triangle (Project Euler 18 and 67) with Python

Project Euler 18 Project Euler 67 As problem 67 is harder, I'll go with that one: By starting at the top of the triangle below and moving to adjacent numbers on the row below, the maximum ...
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find longest common substring in space O(n)

I am working on the class question find the longest common substring from 2 strings but I would like to return the longest common substring instead of just size of longest common substring.like ...
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0answers
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How do I optimize memoization in order to find longest palindromic substring?

I want to find the longest palindromic substring using dynamic programming in Python3. The strings can be as large as this string. I have seen other questions on this problem that successfully solve ...
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2answers
103 views

Rod Cutting Problem Code

I am learning dynamic programming. I read articles for the rod cutting problem and I applied it in cpp, and I got a doubt, does the below code solves the problem through memoization (say, previously ...
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225 views

LeetCode: Shortest Common Supersequence C#

https://leetcode.com/problems/shortest-common-supersequence/ Given two strings str1 and str2, return the shortest string that has both str1 and str2 as subsequences. If multiple answers exist, ...
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377 views

Solution to knapsack problem exceeds time and RAM limits

My goal is to code the knapsack problem algorithm. The problem is that a knapsack has a given weight limit, W. I have a collection of items which have a given ...

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