permutation | 易学教程

Is it possible to get permutations for a String that has repeated characters?

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问题 I am currently using the trotter dart package on flutter, however it is unable to generate all permutations of strings with repeated numbers. It works fine with 1234, but not with 2344. 回答1: (Disclaimer: I'm the author of trotter . Thanks for your interest in my library!) When dealing with a moderate number of items, we can simply create a mapping from a regular sequence of permutations of indices to respective items in an arbitrary list. In this case, the arbitrary list contains the items in

Generating all permutations of a certain length

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问题 Suppose we have an alphabet "abcdefghiklimnop". How can I recursively generate permutations with repetition of this alphabet in groups of FIVE in an efficient way? I have been struggling with this a few days now. Any feedback would be helpful. Essentially this is the same as: Generating all permutations of a given string However, I just want the permutations in lengths of FIVE of the entire string. And I have not been able to figure this out. SO for all substrings of length 5 of

Obtain a Permutation 乱搞

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题意：给定一个矩阵，问最少能用多少次操作使得矩阵有序(类似离散化坐标）操作一: 修改一个元素的值操作二：将矩阵的一列上移 #include<bits/stdc++.h> using namespace std; typedef long long ll; const ll mod=1e9+7; const int N=1e6+100; map<int,int>mp; int main() { int n,m; cin>>n>>m; int a[2*n+1][m+1]; for(int i=1;i<=n;i++) for(int j=1;j<=m;j++) scanf("%d",&a[i][j]),a[i+n][j]=a[i][j]; int ans=0; for(int temp,j=1;j<=m;j++,ans+=temp) { temp=n; mp.clear(); for(int i=1;i<=2*n;i++) a[i][j]-=(i-1)*m; for(int i=1;i<=n;i++) mp[a[i][j]]++; for(int i=1;i<=n;i++) { temp=min(temp,i-1+n-mp[j-(i-1)*m]); --mp[a[i][j]]; ++mp[a[i+n][j]]; } } cout<<ans; } View Code 来源：

Finding A List of All Combinations of 6 Numbers That Add up to 10

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问题 So I've seen similar versions of this question asked before (Getting all combinations which sum up to 100 using R) but I'm struggling to find a way to figure out what I need to run specifically. I'm trying to create a list in R of all the different combinations of 6 numbers that add up to 10. However, I want to include 0s and repeats of the same # in the row. So it would look something like this: 10 0 0 0 0 0 9 1 0 0 0 0 8 2 0 0 0 0 I've tried running the following: C = t(restrictedparts(10,6

Finding A List of All Combinations of 6 Numbers That Add up to 10

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How do I make this combinations/permutations method recursive?

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问题 I have an arraylist of Strings that want to have all possible combinations stored into another collection. For example: [air,bus,car] -> [air] [bus] [car] [air,bus] [air,car] [bus,air] [bus,car] [car,air] [car,bus] [air,bus,car] [air,car,bus] ... [car,bus,air] Repetitions are not important. The code right now I have is: public ArrayList<String> comb(ArrayList<String> wrds, ArrayList<String> str, int size) { ArrayList<String> s = new ArrayList<String>(); s.addAll(str); if(size != a1.size()) {

Find unique rows of a cell array considering all possible permutations on each row

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问题 I have cell array A of dimension m * k . I want to keep the rows of A unique up to an order of the k cells . The "tricky" part is "up to an order of the k cells" : consider the k cells in the i th row of A , A(i,:) ; there could be a row j of A , A(j,:) , that is equivalent to A(i,:) up to a re-ordering of its k cells, meaning that for example if k=4 it could be that: A{i,1}=A{j,2} A{i,2}=A{j,3} A{i,3}=A{j,1} A{i,4}=A{j,4} What I am doing at the moment is: G=[0 -1 1; 0 -1 2; 0 -1 3; 0 -1 4; 0

PHP Generate every 2 character combo of the alphabet. Twist: duplicates letters allowed [closed]

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问题 Closed. This question is off-topic. It is not currently accepting answers. Want to improve this question? Update the question so it's on-topic for Stack Overflow. Closed 6 years ago . I believe there is something like 67 million combination of two character strings using only the letters of the alphabet. I basically want an array in PHP containing something like the following Array ( [1] => AA [2] => AB [3] => AC [4] => AD [5] => AE [6] => AF [7] => AG [8] => AH [9] => AI [10] => AJ .... and

Is there a .NET library that can do string permutations or string expansion?

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问题 What I'm looking for is some library or some code of classes that can be used to expand construction strings into variations and permutations. Something like the following (syntax is mine, may be different): construction string: [Ff]oo [Bbß]ar|F(oo|oe) output strings: Foo Bar foo Bar Foo bar foo bar Foo ßar foo ßar Foo Foe While it wouldn't be too hard to build this myself, if it's around, why bother reinventing the wheel? 回答1: This doesn't follows your syntax, but I use it in some projects

How to make permutation matrix for two lists of str, Python3

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问题 I have two lists. a_num = [1, 3, 2, 4] b_num = [1, 2, 3, 4] I want to find a permutation matrix to convert a to b . Mathematically, a permutation matrix is a square matrix, whose elements are either 1 or 0. It can change the sequence of elements in a vector, by multiplying it. In this particular example, the permutation matrix is: p = [[1,0,0,0], [0,0,1,0], [0,1,0,0], [0,0,0,1]] # check whether p is correct. b_num == np.dot(np.array(p), np.array(a_num).reshape(4,1)) Could you please show me