2018上海大都会赛J-Beautiful Numbers

模运算比较慢

#include<bits/stdc++.h>
using namespace std;
typedef long long LL;
int bit[20];
LL dp[20][105][105];

int gcd(int a,int b) {return b==0?a:gcd(b,a%b);}
int lcm(int a,int b) {return a/gcd(a,b)*b;}

LL dfs(int pos,int sum,int rem,bool limit){
    if(pos<=0) return sum==mod&&rem==0;
    if(!limit&&dp[pos][sum][rem]!=-1)
        return dp[pos][sum][rem];
    LL ans=0;
    int now;
    int up=limit?bit[pos]:9;
    for(int i=0;i<=up&&i<=mod-sum;i++){
        now=(rem*10+i)%mod;
        ans=ans+dfs(pos-1,sum+i,now,limit&&i==bit[pos]);
    }
    if(!limit) dp[pos][sum][rem]=ans;
    return ans;
}

LL solve(LL x){
    int len=0;
    while(x){
        bit[++len]=x%10;
        x/=10;
    }
    LL ans=0;
    for(int i=1;i<=9*len;i++){
        memset(dp,-1,sizeof(dp));
        mod=i;
        ans+=dfs(len,0,0,true);
    }
    return ans;
}

int main(){
    int T;
    scanf("%d",&T);
    int cas=1;
    LL n;
    while(T--){
        scanf("%lld",&n);
        printf("Case %d: %lld\n",cas++,solve(n));
    }
    return 0;
}