高精度幂POJ

Posted 2020-12-24 jiazizheng

#include<bits/stdc++.h>

using namespace std;

string s;

int n,z,len,y,a[10000],b,k;

void multi(int b){

    for(int i=1;i<=len;i++)a[i]*=b;

    for(int i=1;i<=len-1;i++)a[i+1]+=a[i]/10,a[i]%=10;

    while(a[len]>=10)a[len+1]=a[len]/10,a[len]%=10,len++;

}

int main(){

    while(cin>>s>>n){

        memset(a,0,sizeof(a));b=k=len=y=0;

        if(n==0){cout<<1<<endl;continue;}

        for(int i=0;i<6;i++)if(s[i]==‘.‘){z=i;break;}

        while(s[s.size()-1]==‘0‘)s.erase(s.size()-1,1);

        len=s.size();s.erase(z,1);y=len-z-1;k=y*n;len--;

        for(int i=0;i<len;i++)a[len-i]=s[i]-‘0‘,b=b*10+s[i]-‘0‘;

        for(int i=2;i<=n;i++)multi(b);

        for(int i=len;i>k;i--)cout<<a[i];

        if(k!=0)cout<<‘.‘;

        for(int i=k;i>=1;i--)cout<<a[i];

        puts("");  

    }

    return 0;

}