【zoj-3962】Seven Segment Display

比賽時推了一個巨麻煩的公式，結束後纔想到可以利用前綴和思想簡化。

#include<bits/stdc++.h>
#define rep(i,n) for(int i=1;i<=n;i++)
#define fi first
#define se second
#define pr pair<int,int>

using namespace std;
typedef long long ll;

const int N=200005;
ll n,m,k,x,y,tms,Hx=1;
ll hx[20],sum[50];
string s;
int num[]={6,2,5,5,4,5,6,3,7,6,6,5,4,5,5,4};

int getnum(char ch) {
    if(ch>='A'&&ch<='F') return ch-'A'+10;
    return ch-'0';
}

ll wk(ll n) {
    if(n<0) return 0;
    ll _n=0,hx=1;
    ll _tms=1,t=0,ans=(n+1)*48;
    rep(i,8) {
        t=n%16,n/=16;
        ans+=_tms*sum[max(t-1,0LL)]+t*(i-1)*_tms/16*tms+(num[t]-6)*(_n+1);
        _tms*=16,_n+=t*hx,hx*=16;
    }
    return ans;
}

int getdit(char c) {
    if(c>='A') return c-'A'+10;
    return c-'0';
}

ll getnum(string &s) {
    ll ans=0,t=1;
    rep(i,8) ans+=getdit(s[i-1])*t,t*=16;
    return ans;
}

void solve(ll ans=0,int t=0) {
    cin>>n>>s;
    reverse(s.begin(),s.end());
    ll num=getnum(s);
    if(num+n-1>=Hx) {
        ll nm=(num+n-1)%Hx;
        cout<<wk(Hx-1)-wk(num-1)+wk(nm)<<endl;
    }
    else cout<<wk(num+n-1)-wk(num-1)<<endl;
}

int main() {
    ios::sync_with_stdio(false);
    rep(i,8) Hx*=16;
    rep(i,15) sum[i]=sum[i-1]+num[i]-6;
    tms=sum[15];
    int T;cin>>T;
    while(T--) solve();
}