It's a Mod, Mod, Mod, Mod World （类欧几里得模板题

https://vjudge.net/contest/317000#problem/F

#include <iostream>
#include <cstdio>
#include <queue>
#include <algorithm>
#include <cmath>
#include <cstring>
#define inf 2147483647
#define P 998244353
#define p(a) putchar(a)
#define For(i,a,b) for(long long i=a;i<=b;++i)

using namespace std;
long long T;
long long n,a,b,c;
struct data{
    long long f,g,h;
    data calc(long long n,long long a,long long b,long long c){
         long long ac = a / c, bc = b / c, m = (a * n + b) / c, n1 = n + , n21 = n *  + ;
         data d;
         if (a == ) {
            d.f = bc * n1;
            d.g = bc * n * n1 /;
            d.h = bc * bc * n1;
            return d;
        }

        if (a >= c || b >= c){
            d.f = n * n1 / * ac + bc * n1;
            d.g = ac * n * n1 * n21 / + bc * n * n1 / ;
            d.h = ac * ac * n * n1 * n21 / + bc * bc * n1 + ac * bc * n * n1;
            data e = calc(n, a % c, b % c, c);
            d.h += e.h +  * bc * e.f +  * ac * e.g;
            d.g += e.g, d.f += e.f;
            return d;
        }

        data e = calc(m - , c, c - b - , a);
        d.f = n * m - e.f, d.f = d.f;
        d.g = m * n * n1 - e.h - e.f, d.g = d.g /;
        d.h = n * m * (m + ) -  * e.g -  * e.f - d.f;
        return d;
    }
}ans1,ans2;

void in(long long &x){
    long long y=;char c=getchar();x=;
    while(c<''||c>''){if(c=='-')y=-;c=getchar();}
    while(c<=''&&c>=''){ x=(x<<)+(x<<)+c-'';c=getchar();}
    x*=y;
}
void o(long long x){
    if(x<){p('-');x=-x;}
    if(x>)o(x/);
    p(x%+'');
}

signed main(){
    in(T);
    while(T--){
        in(a);in(c);in(n);
        ans1=ans1.calc(n,a,,);
        ans2=ans2.calc(n,a,,c);
        o(ans1.f-c*ans2.f);p('\n');
    }
    return ;
}