bzoj 1072: [SCOI2007]排列perm 状压dp

Posted 2020-11-21 guangheli

code: 

#include <bits/stdc++.h>  
#define N 1005    
using namespace std;  
void setIO(string s) 
{
	string in=s+".in";  
	string out=s+".out"; 
	freopen(in.c_str(),"r",stdin); 
	// freopen(out.c_str(),"W",stdout); 
} 
char str[N]; 
int num[N],f[N<<1][N],poww[N],tax[11],fac[N],vis[11];            
void solve() 
{ 
	memset(f,0,sizeof(f)); 
	memset(tax,0,sizeof(tax));  
	memset(vis,0,sizeof(vis));      
	int mod,i,j,n,k;    
	scanf("%s%d",str,&mod); 
	n=strlen(str);   
	fac[0]=poww[0]=1; 
	for(i=1;i<=10;++i)  fac[i]=fac[i-1]*i;    
	for(i=1;i<=n;++i)   poww[i]=poww[i-1]*10%mod;   
	for(i=0;i<n;++i)    num[i]=str[i]-‘0‘, ++tax[num[i]];     
	f[0][0]=1;                             
	for(i=0;i<(1<<n);++i)  
	{   
		for(j=0;j<mod;++j) 
		{          
			int sz=0;   
			for(k=0;k<n;++k)   if(i&(1<<k)) ++sz;   
			for(k=0;k<n;++k) 
			{
				if(i&(1<<k)) continue;    
				else
				{
					int nx=i|(1<<k);   
					int cur=num[k];    
					f[nx][(j+cur*poww[sz]%mod)%mod]+=f[i][j];    
				}
			}
		}
	}       
	int ans=f[(1<<n)-1][0];
	for(i=0;i<n;++i)   if(!vis[num[i]])   vis[num[i]]=1, ans/=fac[tax[num[i]]];   
	printf("%d
",ans);    
}
int main() 
{ 
	// setIO("input"); 
	int T; 
	scanf("%d",&T);   
	while(T--) 
	{ 
		solve();      
	}
	return 0; 
}