Submission #20548467

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Source Code Expand

#include <bits/stdc++.h>
#define ll long long
#define pb push_back
#define INF 1e10
#define ft first
#define sec second
#define pr pair<int,int>
#define ISCC ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
using namespace std;
int n ,m ,cnt1[10] ,cnt2[10];
string s ,t;
int main() 
{
	cin >> n;
	getchar(); 
	ll tak = 0 ,aok = 0;
	getline(cin ,s); getline(cin ,t);
	for(int i=0 ;i<4 ;i++)
	{
		cnt1[s[i]-'0']++;
		cnt2[t[i]-'0']++;
	}
	for(int i=1 ;i<10 ;i++)
	{
		tak += pow(10,cnt1[i])*i;
		aok += pow(10,cnt2[i])*i;
	}
	double ans=0;
	for(int i=1 ;i<=9 ;i++)
	{
		int tp1 = tak;
		tp1 -= pow(10,cnt1[i])*i;
		tp1 += pow(10,cnt1[i]+1)*i;
		for(int j=1 ;j<=9 ;j++) if(n-cnt1[i]-cnt2[i] > 0 && n-cnt1[j]-cnt2[j] > 0)
		{
			int tp2 = aok;
			tp2 -= pow(10,cnt2[j])*j;
			tp2 += pow(10,cnt2[j]+1)*j;
			if(tp1 > tp2) 
			{
				double a = 9.0*n - 8;
				ans += ((n - cnt1[i] - cnt2[i]) / a) * 
				((n - cnt1[j] - cnt2[j] - (i==j)) / (a - 1));
			}			
		}
	}
	printf("%.9f" ,ans);
}

Submission Info

Judge Result