powerset

问题 This question already has answers here : How to get all subsets of a set? (powerset) (17 answers) Closed 2 years ago . I am trying to implement a function to generate the powerset of a list xs . The general idea is that we walk through the elements of xs and choose whether to include x or not. The problem I'm facing is that withX ends up being equal to [None] (a singleton list with None ) because (I think) s.add(x) returns None . This isn't a homework assignment, it's an exercise in Cracking

问题 This question already has answers here : How to get all subsets of a set? (powerset) (17 answers) Closed 2 years ago . I am trying to implement a function to generate the powerset of a list xs . The general idea is that we walk through the elements of xs and choose whether to include x or not. The problem I'm facing is that withX ends up being equal to [None] (a singleton list with None ) because (I think) s.add(x) returns None . This isn't a homework assignment, it's an exercise in Cracking

问题 I need a t-sql code to get powerset of a resultset. example input : ColumnName 1 2 3 Example Output(one columns as nvarchar) : 1 2 3 1,2 1,3 2,3 1,2,3 Output set may contain duplicate values such as (1,3 vs 3,1). 回答1: You can use this one and get full powerset. Enjoy it. --EXEC PowerSet 'A,B,C,D' Create PROCEDURE PowerSet(@Members NVARCHAR(64)) As Begin Declare @SubSet NVARCHAR(Max), @SubSetCount int, @Counter1 int, @Counter2 int, @ID int Create table #Members ( ID int IDENTITY(1,1) PRIMARY

问题 I have to write a brute-force implementation of the knapsack problem. Here's the pseudocode: computeMaxProfit(weight_capacity) max_profit = 0 S = {} // Each element of S is a weight-profit pair. while true if the sum of the weights in S <= weight_capacity if the sum of the profits in S > max_profit update max_profit if S contains all items // Then there is no next subset to generate return max generate the next subset S While the algorithm is fairly easy to implement, I haven't the slightest

问题 I am studying for an interview and I stumbled upon this question online under the "Math" category. Generate power set of given set: int A[] = {1,2,3,4,5}; int N = 5; int Total = 1 << N; for ( int i = 0; i < Total; i++ ) { for ( int j = 0; j < N; j++) { if ( (i >> j) & 1 ) cout << A[j]; } cout <<endl; } Please I do not want an explicit answer. I just want clarifications and hints on how to approach this problem. I checked power set algorithm on google and I still do not understand how to

问题 I have an array that looks like this: [0, 1, 2, 3, 4, 5, ...] I need a function that will give me an array like this: [ [[0, 1, 2, 3, 4, 5]], [[0, 1, 2, 3, 4], [ 5 ]], [[0, 1, 2, 3], [ 4, 5 ]], [[0, 1, 2], [ 3, 4, 5 ]], ... [[0, 1, 2], [ 3, 4 ], [ 5 ]], ... [[ 0 ], [ 1 ], [ 2 ], [ 3 ], [ 4 ], [ 5 ]] ] Of course this output is only for 6 elements. If you look at the 2nd, 3rd and 4th line of the output array, it's some sort of combination into 2 sub-arrays. If you look at the 6th line of the

问题 I'm trying to generate the powerset of a set and I wrote this code. The problem is, when user enter two similar member of the set it dosen't work properly. What can I do? Here is my code: #include <iostream> #include <string.h> #include <stdio.h> #include <stdlib.h> #include <math.h> using namespace std; char obtain(char *p,int n) { int i; for(i=0;i<n;i++) { cout<<"enter member"<<(i+1)<<"\n"; cin>>*(p+i); } return *p; } void set_display(char *p,int n) { cout<<"{"; for(int i=0;i<n;i++) { cout<

问题 This page provides a power set implementation in shell, and here is my take on it: pa() { if [ "$#" = 0 ] then echo else ( shift pa "$@" ) | while read qu do printf '%s %s\n%s\n' "$1" "$qu" "$qu" done fi } pa x y z I thought it was interesting that the author of the above page made this comment: no nice AWK solution. You are welcome to email me one: <his email> Can this not be done in AWK, or does the shell just do a better job here? 回答1: Here is another AWK approach: echo a b c | awk '{for(i

问题 I'm trying to write python code to print the powerset of a string, but am running into some bugs. Here's what I've got: def getperm (string): perm = [] if len(string) == 0: perm.append("") return perm #if len(string) == 1: # perm.append(string) # perm.append("") first = string[0] print "first = " + str(first) rem = string[1:len(string)] print "rem = " + str(rem) words = getperm(rem) for word in words: for i in range(len(word)): temp = string[0:i] + first + string[i:len(string)] print "temp =

问题 Given an array of elements in PHP, I wish to create a new two-dimensional array containing only those elements of the power set that are a specific length. As an example, for the following array: array(4) { 0 => 'A', 1 => 'B', 2 => 'C', 3 => 'D' } If I were to run the function fixed_length_power_set( $arr, 2 ) then I want it to return: array(6) { 0 => array(2) { 0 => 'A', 1 => 'B' } 1 => array(2) { 0 => 'A', 1 => 'C' } 2 => array(2) { 0 => 'A', 1 => 'D' } 3 => array(2) { 0 => 'B', 1 => 'C' }