COSO1 C++

#include<bits/stdc++.h>
using namespace std;

int r;
string s;

void nhap()
{
    cin>>s;
    cin>>r;
}

void giai()
{
    long long p[20],res=0;
    int x;
    int n=s.length();
    p[0]=1;
    for(int i=1;i<=n;i++) p[i]=p[i-1]*r;
    for(int i=0;i<=n-1;i++)
    {
        if('0'<=s[i]&&s[i]<='9') x=int(s[i])-48;
        else x=int(s[i])-55;
        res=res+p[n-1-i]*x;
    }
    cout<<res<<endl;
}

int main()
{
    freopen("coso1.inp","r",stdin);
    freopen("coso1.out","w",stdout);
    int t;
    cin>>t;
    for(int i=1;i<=t;i++)
    {
        nhap();
        giai();
    }

}