UVA 10900 So do you want to be a 2^n-aire?

#include<bits/stdc++.h>

#include<stdio.h>

#include<iostream>

#include<cmath>

#include<math.h>

#include<queue>

#include<set>

#include<map>

#include<iomanip>

#include<algorithm>

#include<stack>

#define inf 0x3f3f3f3f

using namespace std;

typedef long long ll;

double t;int n;

double ans;

ll mypow(int a,int b)

{

    ll res=1;

    while(b--)res*=a;

    return res;

}

double f[33];

int main()

{

#ifndef ONLINE_JUDGE

    freopen("in.txt","r",stdin);

#endif // ONLIN

    double p0,p1;

    while(cin>>n>>t)

    {

        if(n==0)break;

        f[n]=1.0*mypow(2,n);

        for(int i=n-1;i>=0;i--)

        {

            p0=max(t,1.0*mypow(2,i)/f[i+1]);

            p1=(p0-t)/(1-t);

            f[i]=mypow(2,i)*p1+(1+p0)/2*f[i+1]*(1-p1);

        }

        printf("%.3f\n",f[0]);

    }

}

巴特西

UVA 10900 So do you want to be a 2^n-aire?

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