View difference between Paste ID: 55dUrLaJ and 9BtZRWvx

 #include <iostream>
 #include <cstring>
 #include <string>
 #include <algorithm>
 #include <map>
 #include <vector>
 #include <set>
 #include <queue>
 #include <cstdlib>
 #include <cstdio>
 using namespace std;
 const int maxn = 507;
 
 vector<string> S;
 map<string, int> idx;
 
 vector<int> g[maxn];
 bool used[maxn];
-int d[maxn], p[maxn];
+int d[maxn];
 int bfs(int st)
 {
     memset(used, 0, sizeof(used));
     memset(d, 0, sizeof(d));
-    memset(p, -1, sizeof(p));
+
     Q.push(st);
     d[st] = 0;
     used[st] = true;
     while (!Q.empty())
     {
         int v = Q.front();
         Q.pop();
 
         for (int i = 0; i < g[v].size(); ++i)
         {
             int to = g[v][i];
             if (!used[to])
             {
                 Q.push(to);
                 d[to] = d[v] + 1;
                 used[to] = true;
-                p[to] = v;
+
             else
             {
-            else if (to != p[v])
+
             }
         }
     }
     return 0;
 }
 
 int main()
 {
     //freopen("input.txt", "r", stdin);
     int n;
     cin >> n;
     vector<pair<string, string> > Q;
     for (int i = 0; i < n; ++i)
     {
         string a, b;
         cin >> a >> b;
         Q.push_back(make_pair(a, b));
         S.push_back(a);
         S.push_back(b);
     }
     sort(S.begin(), S.end());
     S.resize(distance(S.begin(), unique(S.begin(), S.end())));
 
     for (int i = 0; i < (int)S.size(); ++i)
     {
         idx[S[i]] = i;
     }
 
     for (int i = 0; i < n; ++i)
     {
         int a = idx[Q[i].first],
             b = idx[Q[i].second];
         g[a].push_back(b);
     }
 
-        g[b].push_back(a);
+
     for (int i = 0; i < (int)S.size(); ++i)
     {
         ans = max(ans, bfs(i));
     }
     if (ans < 3)
     {
         cout << 0;
     }
     else
     {
         cout << ans;
     }
 
     return 0;
 }