Bar Codes

http://acm.hust.edu.cn/vjudge/contest/view.action?cid=31329#problem/N

#include<map>#include<set>#include<list>#include<cmath>#include<ctime>#include<deque>#include<stack>#include<bitset>#include<cstdio>#include<vector>#include<cstdlib>#include<cstring>#include<iomanip>#include<numeric>#include<sstream>#include<utility>#include<iostream>#include<algorithm>#include<functional>using namespace std ;int n , k , m ;const int maxn = 55 ;long long f[ maxn ][ maxn ] ;int main(){while( scanf( "%d%d%d" , &n , &k , &m ) != EOF ){memset( f , 0 , sizeof( f ) ) ;for( int i = 0 ; i <= n && i <= m  ; ++i ){f[ 1 ][ i ] = 1 ;}for( int i = 2 ; i <= k ; ++i ){for( int j = i ; j <= n ; ++j ){for( int k = 1 ; k <= m && j - k > 0 ; ++k ){f[ i ][ j ] += f[ i - 1][ j - k ] ;}}}printf( "%lld\n" , f[ k ][ n ] ) ;}return 0 ;}