学步园

组合数学问题

#include <cstdio>
#include <iostream>
#include <cstring>
#include <algorithm>
#define mod 20130303
typedef long long ll;
using namespace std;
char s[1010];
int d,len;   //之前RE因为这里d,len都定义成char类型...
int vis[10];
ll c[1010][1010];

void init(){
    int i,j;
    for(i=0;i<=1000;i++)
        c[i][0]=1;
    for(i=1;i<=1000;i++)
        for(j=1;j<=i;j++)
            c[i][j]=(c[i-1][j-1]+c[i-1][j])%mod;
}

ll count(){
    int i,all=0;
    ll ans=1;
    for(i=0;i<10;i++)
        all+=vis[i];
    for(i=0;i<10;i++){
        ans=(ans*c[all][vis[i]])%mod;
        all-=vis[i];
    }
    return ans;
}

ll solve(){
    ll tem=0;
    int i;
    for(i=1;i<10;i++){
        if(vis[i]){
            vis[i]--;
            tem=(tem+count())%mod;
            vis[i]++;
        }
    }
    return tem;
}

ll dfs(int pos){
    int i,j;
    ll tem=0;
    if(pos==len)return 0;
    if(pos==0)i=1;
    else i=0;
    for(j=i;j<s[pos]-'0';j++){
        if(vis[j]){
            vis[j]--;
            tem=(tem+count())%mod;
            vis[j]++;
        }
    }
    vis[j]--;
    tem=(tem+dfs(pos+1))%mod;
    return tem;
}

int main(){
    int t,T,i;
    //freopen("a.txt","r",stdin);
    //freopen("b.txt","w",stdout);
    init();
    scanf("%d",&T);
    for(t=1;t<=T;t++){
        scanf("%s %d",s,&d);
        len=strlen(s);
        memset(vis,0,sizeof(vis));
        for(i=0;i<len;i++)
            vis[s[i]-'0']++;
        int tem=vis[d];
        ll sum=0;
        for(i=0;i<tem;i++){
            vis[d]=i;
            sum=(sum+solve())%mod;
        }
        vis[d]=tem;
        sum=(sum+dfs(0))%mod;
        cout<<sum<<endl;
    }
    return 0;
}