hdu 5229 找规律

 1 #include <iostream>
 2 #include<cstring>
 3 #include<map>
 4 #include<vector>
 5 using namespace std;
 6 string s;
 7 int T,N,l;
 8 int ee[20010],oo[20010];
 9 string ss[20010];
10 
11 int gcd(int a,int b)
12 {
13     if(a<b) swap(a,b);
14     if(b==0)    return a;
15     else return (gcd(b,a%b));
16 }
17 
18 int main()
19 {
20     cin>>T;
21     while(T--)
22     {
23         memset(ee,0,sizeof(ee));
24         memset(oo,0,sizeof(oo));
25         map<string,int>  ht;
26         cin>>N;
27         int le=0,lo=0,lx=0;
28         for(int i=1;i<=N;i++)
29         {
30             cin>>s;
31             ss[i]=s;
32             l=s.length();
33             if(ht.count(s))
34             {
35                 //cout<<ht[s]<<endl;
36                 lx+=ht[s];
37                 ht[s]++;
38             }
39             else
40                 ht.insert(pair<string,int>(s,1));
41             if(l%2==0)
42             {
43                 ee[i]=1;
44                 le++;
45             }
46             else
47             {
48                 oo[i]=1;
49                 lo++;
50             }
51         }
52         //int lx=le*(le-1)/2+lo*(lo-1)/2;
53         lx+=le*lo;
54         int ly=N*(N-1)/2;
55         //cout<<le<<" "<<lo<<" -- "<<lx<<" "<<ly<<endl;
56         int gg=gcd(lx,ly);
57         lx=lx/gg;    ly=ly/gg;
58         cout<<lx<<"/"<<ly<<endl;
59     }
60     return 0;
61 }