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# Questions tagged [dynamic-programming]

Questions about problems that can be solved by combining recursively obtained solutions of subproblems.

141 questions with no upvoted or accepted answers
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### Finding the longest repeating subsequence

Given a string $s$, I would like to find the longest repeating (at least twice) subsequence. That is, I would like to find a string $w$ which is a subsequence (doesn't have to be a contiguous) of $s$ ...
317 views

### How can the shortest traveling salesman tour be found in $O(2^n poly(n))$ time and less than exponential space?

I'm stuck on problem 9.4 from The Nature of Computation which reads: Dynamic Salesman. A naive search algorithm for TSP takes $O(n!)$ time to check all tours. Use dynamic programming to reduce this ...
609 views

### Chained operations on sequences with two operators

Given a binary expresion tree, with addition and multiplication operations, how can we optimize it's evaluation? Can we learn from matrix chain multiplication? A generalization of matrix chain ...
247 views

34 views

### Static management of dynamic memory

I have some issue but I can't identify a way to solve it. I wanted to ask you what kind of problem it is? We have a resource - contiguous computer memory. Also we have users which require some ...
112 views

### Coloring of a K-ary tree using minimum paint Buckets

I was recently asked this problem in an interview and I couldn't solve it. Need some help on how to solve this problem. Given a K-ary tree with N nodes (N <= 2000 and K <= 12) you need to ...
99 views

### Shortest sequence over alphabet $\{1, 2, …, k\}$ which is not a subsequence of $A$ and $B$

I have two sequences - $A$ (of length $n$) and $B$ (of length $m$). They consist of numbers from the alphabet $\{1, 2, ..., k\}$. How want to find the shortest sequence $C$ such that $C$ is not a ...
110 views

### One variant of the Knapsack Problem

We have a normal knapsack problem but we can choose up to $t_i$ of the $i$-th object. How would you solve this problem with complexity less than $O(V(n + \sigma(t_i)))$ where $n$ is number of objects ...
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### How to compare A* with DP approach in finding shortest Path?

Consider a hypercube defined over $n$ dimensions where the edges are associated to strictly positive weights, and nodes are marked with $n$ bit-strings, e.g. the source is marked as (0,0,0) in a 3-...
133 views

### Given a set of integers $S$ and a target number $T$, find a subset of $S$ that adds up exactly to $T$ in $O(nT)$ time

Given a set of integers $S=\{s_1,s_2,...,s_n\}$ and a target number $T$, find a subset of $S$ that adds up exactly to $T$ in $O(nT)$ time. I am not quite sure how to solve this but I think I have the ...
83 views

### Finding maximum information gain subinterval of an array containing points from 2 classes

Suppose we have an $N \times 2$ array $A$ where the two entries $A(k,1)$ and $A(k,2)$ give the number of occurrences of each of two classes at position $k$. Given a sub-interval $I$ of indices between ...
48 views

### Training a model to match two time series

Context I have two related time series, I want to learn to produce one from the other. However, they aren't synchronous, and the lag between the two does not revert to the mean, it accumulates. ...
572 views

### Job scheduling problem in O(n log n)

There are $n \leq 10^6$ kinds of cake layers, and for each kind we have a machine capable of baking it in one unit of time and nothing more. Now, a cake is a sequence of layers, more specificly a ...
32 views

### How does the asterisk (*) work in the wildcard matching problem?

This is a wildcard matching problem. Given a pattern P containing letters and character * that can match an arbitrary string of characters (including an empty string), my task is to write a polynomial-...
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### Determining the DP subproblem given a problem

I'm reviewing DP and I was wondering the intuition behind determining the subproblems for some DP problems. For example, consider 2 similar problems. Given a set of 1, 2, and 3 steps you can take, ...
92 views

### Given matrix, count paths visiting each number exactly once

We are given matrix of size at most $21$ by $21$, each number of the matrix is either $-1$, which means empty element, or integer between $1$ and $21$. Each integer may occure several more times in ...
I'm doing a research on a finite horizon decision problem with $t=1,\dots,40$ periods. In every time step $t$, the (only) agent has to chose an action $a(t) \in A(t)$, while the agent is in state \$s(t)...