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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5
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3answers
239 views

Largest contiguous sub-array sum

Challenge Determine the largest contiguous sum of integers in a list. Specifications The first argument is a path to a file. The file contains multiple lines. Each line is a test case represented ...
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2answers
2k views

Obtaining a target number only using the operations ×2, ×3, and +1

Problem Introduction 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 ...
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2answers
435 views

Code for calculating number of trailing zeroes after factorial

While trying my hands at the beginner codechef problem I came across this . So basically doing that problem with Dynamic programming is an overkill but why not try that and get some DP practice. Nice,...
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6answers
2k views

Yet another Fibonacci number generator

First attempt at dynamic programming. I want to make this run faster and better. fibonacci.cpp ...
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2answers
1k views

Change-making problem with specific constraints

I am a new Pythoner. I have solved a OJ project with Python. Can you tell me how can I solve it more Pythonically? Problem Description: There are n coin denominations, each with an unlimited ...
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1answer
281 views

Simple Factor Class

I have a class which lazily factors numbers. It provides the user with these methods: getFactors returns a ...
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2answers
145 views

Count the number of ways to obtain a sum, with consecutivity restriction

A cricketer can score 1, 2, 4 or 6 in a ball. Find in how many ways the player can score a total of "n" runs without hitting 3 consecutive boundaries. Note: Scoring 4 or 6 is considered as a boundary. ...
3
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1answer
334 views

Number of unique sequences of 3 digits, given a length is equal to sum

This is the "Minion's bored game" problem from Google's "Foobar challenge": There you have it. Yet another pointless "bored" game created by the bored minions of Professor Boolean. The game is ...
2
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1answer
547 views

Longest Increasing Sub-Sequence using Dynamic Programming in Python

I wrote the following function to find the longest increasing sub-sequence in an array (tuple, it doesn't work for a list since a list is mutable and it stores the results in a dictionary.). It uses ...
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0answers
330 views

Shortest bitonic tour

This a solution to the shortest bitonic tour using dynamic programming. Bitonic tour starts at the leftmost point then goes strictly rightward to the rightmost point and finally strictly leftward to ...
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2answers
1k views

Rod-Cutting Problem using dynamic programming

I wrote the following code for solving the Rod-Cutting Problem using dynamic programming: Rod Cutting Problem: Given a rod of length n inches and an array of prices that contains prices of all ...
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0answers
302 views

Longest palindrome subsequence

This algorithm finds the longest palindrome that is a subsequence of a given input string in \$\Theta(n^2)\$. Example Input: character Output: ...
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2answers
371 views

google foo.bar max path algorithm puzzle optimization [closed]

I got a programming puzzle described as follows: Save Beta Rabbit Oh no! The mad Professor Boolean has trapped Beta Rabbit in an NxN grid of rooms. In the center of each room (except for the ...
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2answers
3k views

Candie distribution algorithm

I am studying algorithms and I solved this problem under Dynamic Programming section: Alice is a kindergarten teacher. She wants to give some candies to the children in her class. All the ...
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1answer
43 views

Loading URLs via a case statement

I have the following code which loads in a URL based on the id of a user-clicked button. I'm looking to compress it down as much as possible, and make it more modular and reusable: ...
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2answers
1k views

High execution time of LCS length program in Python2

I was trying to solve the Longest Common Subsequence problem on a HackerRank exercise. It's quite simple and straightforward, just print out the length of the LCS. I submitted this code: ...
2
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2answers
73 views

Find the best path amongst N random points

For an application with a graphical canvas, I want to generate N points. But then I want to link those points, and I want to find the best path through those points. I wanted to use a dynamic ...
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1answer
2k views

Levenshtein distance with edit sequence and alignment in Java

I have this program that computes a Levenshtein distance of the two input strings, their edit sequence, and the alignment: LevenshteinEditDistance.java: ...
5
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2answers
420 views

Number of ways to make change for an amount

Task Write a program that, given the amount to make change for and a list of coins prints out how many different ways you can make change from the coins to STDOUT. My approach The number to make ...
2
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1answer
86 views

Optimally allocating a resource with time-varying demand and cost

I'm working on the following DP which finds the optimal way to allocate a resource. At each time step I can either allocate (0.2 resources) at cost C or not in which case the storage is reduced by the ...
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1answer
1k views

Auto registering class registry

I built this auto registering registry to look into a package and import all modules and register any classes that are a subclass of a base class. I use it as a registry for a model's choices in ...
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1answer
2k views

Finding the longest path, avoiding obstacles in a 2D plane

The Scenario You are given a matrix of size m x n (width x height) with m*n spots where there are a few obstacles. Spots with obstacles are marked as 1, and those without are marked as 0. You can ...
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1answer
879 views

Longest contiguous Increasing Subset in java

I have tried to come up with a solution to the longest increasing subsequence problem.Can this solution be optimized further? Example 1: Input: {5,4,3,7,8,9,11} Output: 3, 7, 8, 9, 11 Example 2: ...
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1answer
177 views

0-1 Knapsack in Java

I'm looking for advice on coding practices in general. ...
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5answers
811 views

Pass Triangle challenge

In order to solve this challenge: Challenge Description By starting at the top of the triangle and moving to adjacent numbers on the row below, the maximum total from top to bottom is 27. <...
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2answers
612 views

Dynamic Programming: Fibonacci-like recurrence relation

This is a problem from my Introduction to Algorithms textbook. Consider the infinite sequence of numbers An|n>0 = (1,1,3,4,8,11,...) defined recursively as follows. $$ A_n = \left\{\begin{aligned} &...
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2answers
2k views

Optimal matrix chain multiplication in Java

Preliminaries Given two matrices $$ A = \begin{pmatrix} a_{11} & a_{12} & \dots & a_{1q} \\ a_{21} & a_{22} & \dots & a_{2q} \\ \vdots & \vdots & \ddots & \vdots \\...
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0answers
537 views

Recursive implementation of integer partition without re-arrangement

Problem: Integer partition without re-arrangement Input: An arrangement S of nonnegative numbers {s1, . . . , sn} and an integer ...
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2answers
647 views

Quick Sum TopCoder (Brute Force solution)

Given a string of digits, find the minimum number of additions required for the string to equal some target number. Each addition is the equivalent of inserting a plus sign somewhere into the ...
12
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1answer
351 views

Counting paths in an n-dimensional grid that stay within the boundaries

Problem Statement You are situated in an N dimensional grid at position (x1, x2, …, xN). The dimensions of the grid are (D1, D2, …, DN). In one step, you can walk one step ahead or behind in ...
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0answers
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SPOJ Aliens in a Train

I need to find the largest interval with a value less than a limit Lt. The data is as follows: For every test case T: Number of elements N, limit Lt N number of elements data I wrote the ...
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3answers
3k views

Find the Nth number divisible by only 2,3,5, or 7

I recently participated in a small friendly competition and this was one of the questions: A number whose only prime factors are 2, 3, 5 or 7 is called a humble number. The first 20 humble ...
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1answer
2k views

Implementation of Longest Common Subsequence

So I implemented the LCS algorithm once using a 2-D matrix to store values while the other one used a python dictionary. I found the dictionary implementation was easier to implement and was a more ...
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0answers
663 views

Multiple 0-1 knapsack

I have a problem were the time in minutes of N songs are given and I have to write the maximum number of time in K CDs. Input description The first input line consists of two positive integers N e ...
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1answer
81 views

Construct biggest stacked tower with restriction

Problem The problem is to build the tallest tower made up of cylinders, respecting all the rules. Will be arranged on the table, an amount of \$N\$ cylinders. Each cylinder has one color: Red, ...
3
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1answer
1k views

Subset sum whose set contains only positive integers

I was trying to write a dynamic programming algorithm using a bottom up approach that solves the subset sum problem's version where the solution can be either an empty set and the initial set can only ...
6
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2answers
2k views

Finding the rod pieces in the rod cut issue

I have been reading the chapter 15 of "Introduction to Algorithms" (3rd edition) by Cormen, etc. The chapter 15 is about dynamic programming, and the first example they show us is the "rod cut problem"...
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2answers
911 views

LeetCode Minimum Path Sum algorithm

I am attempting to solve the Minimum Path Sum algorithm problem and I have a working solution, however there was an unwritten requirement that the algorithm not exceed an unspecified amount of time ...
4
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1answer
1k views

HackerRank - Candies

Here is the solution I've written for Hacker Rank Candies challenge. It uses dynamic programming (memoization in a boxed array). I'm interested on what could be done to improve this code in term of ...
4
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3answers
6k views

Calculating the sum of array elements to the left and right

I am using C++ to code the following logic: An Array is given we have to traverse the array such that sum of array elements to its left must be equal to sum of elements to its right. BTW this is ...
6
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3answers
511 views

ChessMetric - Topcoder Challenge

My solution for the topcoder ChessMetric challenge seems really slow. I feel like there should be a better way, but I'm not sure. Challenge Description Suppose you had an n by n chess board ...
4
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1answer
364 views

AvoidRoads - TopCoder Challenge

I'm learning Dynamic Programming, following the topcoder guide. I just solved the AvoidRoads challenge. It passes all the test cases, but I don't have much experience, so I don't know if it's good. ...
8
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2answers
212 views

Minimum number of coins problem using dynamic programming - follow up

I previously posted a code here. It turns out that the code is not following the correct dynamic programming principles and instead it was based on a greedy approach. Hence, I started again, keeping ...
11
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3answers
2k views

Coin Change: Minimum number of coins

Problem: You are given n types of coin denominations of values \$v(1) < v(2) < ... < v(n)\$ (all integers). Assume \$v(1) = 1\$, so you can always make change for any amount of money \$C\$....
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2answers
606 views

BadNeighbors - Topcoder puzzle

I'm learning Dynamic Programming, following the topcoder guide. I just solved the BadNeighbors puzzle. It passes all the test cases, but I don't have much experience, so I don't know if it's good. ...
3
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3answers
163 views

Max contiguous slice in Ruby

I need to compute the max contiguous slice in an array. I wrote this function, but I am not sure if it is correct or I am missing edge cases. I ran several cases. ...
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1answer
7k views

Implementation of Sequence Alignment in C++

Below is my implementation of the dynamic programming solution to the sequence alignment problem in C++11: ...
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5answers
3k views

DP example for “Power of Two” in Python

I'm not familiar with Python but want to provide a code snippet for an SO question about Dynamic Programming. The snippet should show the bottom-up approach of DP. The function ...
11
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1answer
1k views

House-coloring optimization challenge

I have an interview coming up in the next few weeks, and I'm choosing to be interviewed in Python. I began programming in Python (it was about four years ago), so the syntax is natural to me, but I ...
10
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2answers
270 views

Undo format when format disappears

I was posed a question as follows: Given a sentence like "John is a bad man", lets say all the formatting disappears and you are left with one string "johnisabadman". Given a dictionary of words, ...