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2 votes
0 answers
41 views

Dividing $N$ coins into at most $K$ groups such that I can get any number of coins by selecting whole groups

Problem Inspired from Dividing $100$ coins into $7$ groups such that I can choose any number of coins by selecting whole groups . I am interested in the number of possible ways we can get such a split....
EnEm's user avatar
  • 1,171
2 votes
0 answers
73 views

Bin packing : item to be packed in a certain bin depend on previously packed items to that bin.

I am working on an engineering problem. I need to implement an algorithm that looks like a certain variant of bin packing. Specifically, in this variant of the bin packing, the size of a certain item ...
Mazen Ezzeddine's user avatar
2 votes
2 answers
86 views

Is this problem NP-hard?Or what kind of mathematical problem does it belong to?

Assuming there are n types of gifts, each with a number of $a_n$. Now we have to pack them into gift packs, each containing several types of gifts, and each gift has only one.If a gift package ...
ZhuJerry's user avatar
2 votes
0 answers
17 views

Mechanic shop with limited delay capacity

Suppose a mechanic shop serves $M$ customers for $N$ days. Each morning, each customer brings in a number of parts to repair (denoted by $0\leq A_{i,j}\leq A_{max}$). Suppose all parts need to be ...
Andrew Yao's user avatar
0 votes
1 answer
50 views

Checking NP-completeness of the following problem(s)- Assigning candidates to departments

Suppose we have $n$ candidates from a candidate pool $\{1,2, .., n\}$ and we have $m$ departments. Suppose each department $d$ is considering hiring some $C_d \subseteq \{1, 2, ... n\}$ candidates (...
Estaban's user avatar
0 votes
0 answers
160 views

NP completeness of a variant of assignment problem

I have the following variant of assignment problem: Suppose we have $m$ machines and $n$ jobs. Each machine is capable of doing a subset of jobs and each machine $i$ has capacity $C_i$. Each job $j$ ...
Joe's user avatar
  • 422
1 vote
0 answers
11 views

Find Extremal Point over a Set of all Simple Cycle in a Directed Graph

Dearl all, I recently stumbled across an interesting combinatorial problem and was wondering if someone here has faced something similar and would help me get a head start. Problem Defintion Let G be ...
Tomas Ye's user avatar
0 votes
1 answer
136 views

Knapsack problem on 2D or 3D space

Considering a series of rectangle items with known size $(a_1,b_1),(a_2,b_2)\cdots,(a_n,b_n)$, and a big rectangle box with size $(A,B)$ Question 1: How to fill the box with the items that minimize ...
Nothingts's user avatar
0 votes
1 answer
107 views

Is the generalized assignment problem with un-capacitated agents NP-hard?

I am working on a generalized assignment problem which I typed below. I know it is shown to be NP-hard. I am wondering whether the problem is still NP-hard when the capacity of the agents are assumed ...
user2707440's user avatar
8 votes
2 answers
2k views

Minimum transactions to settle debts among friends

You are given $n$ integers $x_1,x_2,\dots,x_n$ satisfying $\sum_{i=1}^n x_i=0$. A legal move is to choose an integer $a$ and two indices $i,j$, and to increase $x_i$ by $a$ and decrease $x_j$ by $a$. ...
Sidi Chang's user avatar
0 votes
2 answers
467 views

Division n items into k boxes prove that it is NP-Complete

I don't know how to solve this problem. Can anyone help me with it please? I need to prove that this is a NP-complete problem. We are given $n$ items with sizes $s_1, s_2, ... ,s_n$, where $0 < ...
Filip Bouška's user avatar
3 votes
1 answer
166 views

NP-complete impossible to solve in $O(n)$

NP-complete problems are likely to be unsolvable in polynomial time (although no one proved it yet). My question is, has anybody proved that they are unsolvable in $O(n^d)$ for some concrete small $d$?...
Valentin's user avatar
  • 265
1 vote
1 answer
68 views

Questions concerning assumptions to conclude that $\operatorname{P}=\operatorname{NP}$

Suppose you find a reduction from the $k$-vertex-cut problem to the hamiltonian-path problem. In particular, you find an algorithm $A$ that, given the graph $G$ and the number $k$, outputs a graph ...
Aaron's user avatar
  • 11
2 votes
1 answer
2k views

How can we show that 3-dimensional matching $\le_p$ exact cover?

In exact cover, we're given some universe of objects and subsets on those objects, and we want to know if a set of the subsets can cover the whole universe such that all selected subsets are pairwise ...
Parker's user avatar
  • 215
4 votes
3 answers
1k views

Using up letters on a refrigerator is NP-complete

You spend some time with your preschool-age daughter trying to use up all of the magnet letters on the refrigerator to spell words that she knows. Formally, you have a set of letters and you are ...
Cortney's user avatar
  • 61