https://ac.nowcoder.com/acm/contest/321#question
代码写得蛮丑的。。真的很丑
像是高中教的veen图，并涉及到容斥原理。
1 #include<cstdio> 2 #include<cmath> 3 #include<cstring> 4 #include<iostream> 5 #include<algorithm> 6 #include<bits/stdc++.h> 7 using namespace std; 8 #define mem(a) memset(a,0,sizeof(a)) 9 #define ll long long 10 #define maxx 1e9 11 ll gcd(ll a,ll k) 12 { 13 if(k == 0) 14 return a; 15 else 16 return gcd(k,a%k); 17 } 18 19 int main() 20 { 21 int t; 22 cin>>t; 23 while(t--) 24 { 25 ll a,b,c,u=maxx; 26 cin>>a>>b>>c; 27 ll cnt=1; 28 ll m,n,p; 29 m=a/gcd(a,b)*b; 30 n=a/gcd(a,c)*c; 31 p=b/gcd(b,c)*c; 32 cnt=cnt/gcd(cnt,a)*a; 33 cnt=cnt/gcd(cnt,b)*b; 34 cnt=cnt/gcd(cnt,c)*c; 35 u=u-(u/a+u/b+u/c-u/m-u/n-u/p+u/cnt); 36 cout<<u<<endl; 37 } 38 39 }