All Questions
Tagged with integer-partitions permutations
34
questions
2
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3
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1k
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Number of ways of cutting a stick such that the longest portion is of length n
We are given a stick of length $L$ (say). We make cuts such that the longest piece is of length $n$ (say) at most.
What are the minimum number of pieces we will get and in how many ways this can be ...
CommunityBot
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10
votes
1
answer
228
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Unexpected result on the number of permutations with a restriction.
Let $p=(p_1,p_2,\dots,p_n)$ be a weak composition of a positive integer number $n$ into $n$ non-negative integer parts and let $k_i$ be the count of the part $i$ ($i=0,1,2,\dots$) in the composition.
...
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1
vote
1
answer
37
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I want to obtain partition of an integer with an initial value and
I want to obtain a partition of an Integer with an initial value and
the value following it is smaller and the value following it is smaller than the previous value and no value repeats itself.
within ...
- 761
0
votes
0
answers
28
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Number of partitions with limited cardinality [duplicate]
We are given $k$ urns labeled from $1$ to $k$. What is the number of ways to put $n$ indistinguishable balls into the $k$ (distinct) urns, given that each urn has a limited capacity equal to $c$, ...
- 3,794
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2
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The number 3 can be written as $3$, $2+1$, $1+2$ or $1+1+1$ in four ways. In how many ways can the number $n$ be written?
Attempt
Let $x$ be any variable
$X+0=n ; X+Y=n ; X+Y+Z=n ; \dots; X+Y+Z+A+\dots=n$ (sum of n-1 terms); $1+1+1+.......+1=n$ (sum of n terms).
So total number of ways=
$$(n-1) C (1-1)+(n-1) C (2-1)+\...
- 39.9k
0
votes
1
answer
58
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Combination with Restriction and Repetition
I have a number $x$, let's say $5$, and I want to sort the number out into $4$ digits so that the sum of the digits is equal to $5$, but the value of each digit cannot exceed $3$. $0$ would be an ...
- 47.4k
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1
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315
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How many ways can you add the numbers 1, 2, and 3 to create a number n?
I would like to find an equation in which, given a number n, you can find the amount of ways to add 1, 2, and 3 to create the number. The commutative rule doesn't apply; for example, 1 + 1 + 3 is a ...
- 47.4k
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votes
0
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How can we map a partition of $n$ to some permutation of [1,2, ... , n]?
Here is the question I was reading:
Does every partition of n correspond to some permutation of [1,2, ... n]?
And here is a statement in the answer given there that I want to use:
If the partition is $...
CommunityBot
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votes
0
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47
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Which of partitions of 5 correspond exclusively to even permutations?
I am ultimately want to prove that $A_{5}$ is simple and the first step in doing so is to:
$(a)$ Write out all partitions of $5.$ Which of these correspond exclusively to even permutations?
I was able ...
CommunityBot
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0
votes
1
answer
54
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Applying boundary conditions to counting combinatorial question [duplicate]
I was trying to count the number of natural number solutions to the equation: $x_1 + x_2 + ... + x_{11} = 20$, such that $0 \leq x_i \leq 9$, for all $i \in \{1, ..., 11\}$.
I know how to apply the ...
- 10.6k
0
votes
1
answer
194
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Integer partitions and permutations
I am given the pair $(n, \lambda)$ where $\lambda$ is a partition of $n$ such that 6 is not a part in $\lambda$. I am told to let $\lambda^*$ represent the partition of $n$ conjugate to $\lambda$. ...
- 36.8k
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26
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Making a group of $p$ people with $n$ available nationalities
Making a group of p people using m out of n available nationalities can be one of these two scenarios;
$m \le p \le n$ or $m \le n \le p$.
Using p,m, and n, how to evaluate the number of ways of ...
- 5,450
1
vote
2
answers
196
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Limit the maximum value of the composition of an integer
I was doing a coding test (already finished, so no cheating for me) and came across this problem, which I'll describe in few steps:
We have a keypad, like on cellphones, with keys from 1 to 9, where ...
- 13.5k
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0
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70
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Number of ways to partition $\{1,2,3, \dots, N\}$ into tuples where the size of no tuple exceeds $3$.
While it seems to me that the general answer is not going to be a neat formula, I really only need this for $N=4$ and $N=5$. I'm getting $61$ and $321$ respectively, but I'm not sure. Please help.
- 17k
-1
votes
1
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Number of ordered set partitions with subset size $\leq 3$
For $n \ge 0$, let $h_n$ be the number of ways of taking $n$ (distinguishable)
rabbits, putting them into identical cages with one to three rabbits per
cage and then ordering the cages in a row. Find ...
- 1,898