Submission #1444718

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Source Code Expand

#include <bits/stdc++.h>
#define REP(i,n) for(int i=0;i<(int)(n);i++)
#define ALL(x) (x).begin(),(x).end()
#define LL long long

using namespace std;






int main(){

    int N;
    cin>>N;
    LL D;
    cin>>D;

    long double pro[3][3]={{1.0/2 , 1.0/3, 1.0/6},
                                 {2.0/3, 1.0/3, 0},
                                 {5.0/6, 1.0/6, 0}};

    int num[3]={0};//(0,1,2) →(2,3,5) の出た回数…
    while(true){
        if(D%2!=0||D==0)break;
        num[0]++;
        D/=2;
    }
    while(true){
        if(D%3!=0||D==0)break;
        num[1]++;
        D/=3;
    }
    while(true){
        if(D%5!=0||D==0)break;
        num[2]++;
        D/=5;
    }

    if(D!=1){
        cout<<0<<endl;
    }else{
        long double dp[3][N+1][201];
        fill(dp[0][0],dp[3][0],0);
        dp[0][0][0]=1;
        dp[1][0][0]=1;
        dp[2][0][0]=1;

        REP(k,3) {
            REP(i, N) {
                REP(j,201){
                    if(j==0)dp[k][i+1][j]=dp[k][i][j];
                    else if(j==1)dp[k][i+1][j]=dp[k][i][j]+(-dp[k][i][j]+dp[k][i][j-1])*(pro[k][1]+pro[k][2]);
                    else dp[k][i+1][j]=dp[k][i][j]+(-dp[k][i][j]+dp[k][i][j-1])*(pro[k][1]+pro[k][2])+(-dp[k][i][j-1]+dp[k][i][j-2])*pro[k][2];
                }
            }
        }

        if(num[0]+num[1]+num[2]>N){
            cout<<0<<endl;
        }else{
            cout<<fixed<<setprecision(10)<<dp[0][N][num[0]]*dp[1][N][num[1]]*dp[2][N][num[2]]<<endl;
        }

    }

    return 0;
}

Submission Info

Judge Result