题目链接：
D - It's a Mod, Mod, Mod, Mod World
Kattis - itsamodmodmodmodworld
具体的每个参数的代表什么直接看题面就好了。
AC代码：
1 #include<bits/stdc++.h> 2 using namespace std; 3 # define ll long long 4 # define inf 0x3f3f3f3f 5 const int maxn = 2e6+100; 6 ll cal(ll a, ll b,ll c,ll n){ 7 if(n<=0)return 0; 8 if(n==1)return (b/c); 9 ll tmp=0; 10 tmp+=(a/c)*((n-1)*n/2); 11 tmp+=(b/c)*n; 12 a=a%c; 13 b=b%c; 14 if(a==0)return tmp; 15 else return (tmp+cal(c,(a*n+b)%c,a,(a*n+b)/c)); 16 } 17 int main(){ 18 int T; 19 scanf("%d",&T); 20 while(T--){ 21 ll p,q,n; 22 scanf("%lld %lld %lld",&p,&q,&n); 23 ll tot=n*(p+p*n)/2ll; 24 ll tmp=cal(p,p,q,n); 25 tmp*=q; 26 printf("%lld ",tot-tmp); 27 } 28 return 0; 29 }