#include <iostream>
#include <iterator>
#include <list>
#include <vector>
#include <algorithm>
using namespace std ;
template <class T , class Iter>
void find_subset( Iter first , Iter last , int n , vector<T>& foo ) {
if ( n == 0 ) {
cout << "( " ;
copy( foo.begin() , foo.end() , ostream_iterator<T>(cout," ") ) ;
cout << ") " ;
} else {
for ( Iter iter = first ; iter != last ; ++iter ) {
foo.push_back( *iter ) ;
++iter ;
find_subset( iter , last , n-1 , foo ) ;
--iter ;
foo.pop_back() ;
}
}
}
template <class T , class Iter>
void power_set( Iter first , Iter last ) {
int no = distance(first,last) ;
cout << "The POWER SET of ( " ;
copy( first , last , ostream_iterator<T>(cout," ") ) ;
cout << ")\n" ;
cout << "> Φ" << endl << endl ;
vector<T> sets ;
for ( int i = 1 ; i <= no ; ++i ) {
sets.resize(0) ;
cout << "> " << i << " element" << ( i == 1 ? " :\n" : "s :\n" ) ;
find_subset( first , last , i , sets ) ;
cout << "\n\n" ;
}
cout << endl ;
}
int main() {
char a[] = "abcdefg" ;
power_set<char,char*>( a , a+6 ) ;
int b[] = { 1 , 2 , 3 , 4 };
power_set<int,int*>( b , b+4 ) ;
list<char> c(a+2,a+5) ;
power_set<char,list<char>::iterator>( c.begin() , c.end() ) ;
return 0 ;
}
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輸 出 |
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The POWER SET of ( a b c d e f )
> Φ
> 1 element :
( a ) ( b ) ( c ) ( d ) ( e ) ( f )
> 2 elements :
( a b ) ( a c ) ( a d ) ( a e ) ( a f ) ( b c ) ( b d ) ( b e ) ( b f ) ( c d ) ( c e ) ( c f ) ( d e ) ( d f ) ( e f )
> 3 elements :
( a b c ) ( a b d ) ( a b e ) ( a b f ) ( a c d ) ( a c e ) ( a c f ) ( a d e ) ( a d f ) ( a e f ) ( b c d ) ( b c e ) ( b c f ) ( b d e ) ( b d f ) ( b e f ) ( c d e ) ( c d f ) ( c e f ) ( d e f )
> 4 elements :
( a b c d ) ( a b c e ) ( a b c f ) ( a b d e ) ( a b d f ) ( a b e f ) ( a c d e ) ( a c d f ) ( a c e f ) ( a d e f ) ( b c d e ) ( b c d f ) ( b c e f ) ( b d e f ) ( c d e f )
> 5 elements :
( a b c d e ) ( a b c d f ) ( a b c e f ) ( a b d e f ) ( a c d e f ) ( b c d e f )
> 6 elements :
( a b c d e f )
The POWER SET of ( 1 2 3 4 )
> Φ
> 1 element :
( 1 ) ( 2 ) ( 3 ) ( 4 )
> 2 elements :
( 1 2 ) ( 1 3 ) ( 1 4 ) ( 2 3 ) ( 2 4 ) ( 3 4 )
> 3 elements :
( 1 2 3 ) ( 1 2 4 ) ( 1 3 4 ) ( 2 3 4 )
> 4 elements :
( 1 2 3 4 )
The POWER SET of ( c d e )
> Φ
> 1 element :
( c ) ( d ) ( e )
> 2 elements :
( c d ) ( c e ) ( d e )
> 3 elements :
( c d e )
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