1287B - Hyperset - CodeForces Solution

#include <bits/stdc++.h>
#define s first
#define cnt second
using namespace std;
typedef long long ll;
unordered_map<string,ll>a;
string s;
ll n,k,i,ans;
int main()
{
    ios::sync_with_stdio(0),cin.tie(0);
    while(cin>>n>>k)
    {
        while(n--)cin>>s,a[s]++;
        ans=0;
        for(auto it=a.begin();it!=a.end();it++)
        {
            for(auto it2=a.begin();it2!=a.end();it2++)
            {
                if(it==it2)continue;
                for(i=0;i<k;i++)
                {
                    if(it->s[i]==it2->s[i])s[i]=it->s[i];
                    else if((it->s[i]=='S'&&it2->s[i]=='T')||(it->s[i]=='T'&&it2->s[i]=='S'))s[i]='E';
                    else if((it->s[i]=='S'&&it2->s[i]=='E')||(it->s[i]=='E'&&it2->s[i]=='S'))s[i]='T';
                    else if((it->s[i]=='E'&&it2->s[i]=='T')||(it->s[i]=='T'&&it2->s[i]=='E'))s[i]='S';
                }
                auto it3=a.find(s);
                if(it3!=a.end()&&it3!=it&&it3!=it2)ans+=it->cnt*it2->cnt*it3->cnt;
            }
        }
        cout<<ans/6<<'\n';
        a.clear();
    }
    return 0;
}