Submission #393334

#	Time	Username	Problem	Language	Result	Execution time	Memory
393334		parsabahrami	Duathlon (APIO18_duathlon)	C++17	8 / 100	85 ms	9632 KiB

count_triplets

    /* There's someone in my head but it's not me */ 
    #include <bits/stdc++.h>
     
    using namespace std;
     
    typedef long long int ll;
    typedef pair<int, int> pii;
     
    #define SZ(x)                       (int) x.size()
    #define F                           first
    #define S                           second
     
    const int N = 1e5 + 10, MOD = 1e9 + 7;
    int s, n, m, M[N], f = 1; vector<int> adj[N];
     
    void DFS(int v) {
        s++;
        M[v] = 1; 
        if (SZ(adj[v]) < 2) f = 0;
        for (int u : adj[v]) 
            if (!M[u]) DFS(u);
    }
     
    int main() {
        scanf("%d%d", &n, &m);
        for (int i = 1; i <= m; i++) {
            int u, v; scanf("%d%d", &u, &v);
            adj[u].push_back(v);
            adj[v].push_back(u); 
            assert(SZ(adj[u]) < 3);
            assert(SZ(adj[v]) < 3);
        }
        ll ret = 0;
        for (int i = 1; i <= n; i++) {
            if (M[i]) continue;
            s = 0, f = 1;
            DFS(i);
            if (f) ret += 1ll * s * (s - 1) * (s - 2);
            else ret += 1ll * s * (s - 1) * (s - 2) / 3;
        }
        printf("%lld\n", ret);
        return 0;
    }

Compilation message (stderr)

count_triplets.cpp: In function 'int main()':
count_triplets.cpp:25:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   25 |         scanf("%d%d", &n, &m);
      |         ~~~~~^~~~~~~~~~~~~~~~
count_triplets.cpp:27:28: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   27 |             int u, v; scanf("%d%d", &u, &v);
      |                       ~~~~~^~~~~~~~~~~~~~~~

• Subtask 1: 0 / 5
• Subtask 2: 0 / 11
• Subtask 3: 8 / 8
• Subtask 4: 0 / 10
• Subtask 5: 0 / 13
• Subtask 6: 0 / 15
• Subtask 7: 0 / 20
• Subtask 8: 0 / 8
• Subtask 9: 0 / 10