Submission #886402

#	Time	Username	Problem	Language	Result	Execution time	Memory
886402		anhphant	Duathlon (APIO18_duathlon)	C++14	0 / 100	1099 ms	1048576 KiB

count_triplets

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define endl '\n'

int inN, inM;
vector<int> inGR[100007];

void initialize() {
    ios_base :: sync_with_stdio(0);
    cin.tie(0); cout.tie(0); cerr.tie(0);
    if (fopen("FILE.INP", "r")) {
        freopen("FILE.INP", "r", stdin);
        freopen("FILE.OUT", "w", stdout);
    }

    cin >> inN >> inM;
    for(int i = 1, u, v; i <= inM; ++i) {
        cin >> u >> v;
        inGR[u].push_back(v);
        inGR[v].push_back(u);
    }
}

int type_determine() {
    if (inN == 10) return 1;
    if (inN == 50) return 2;
}

namespace subtask1 {
    int N, M;
    bool havepath[17][17][17], visited[17];
    vector<int> GR[100007];
    ll ans = 0;

    void backtrack2(ll finish, ll mid, ll start) {
        if (finish != mid) {
            havepath[start][mid][finish] = 1;
        }

        for(int nxtfinish : GR[finish]) {
            if (visited[nxtfinish]) continue;
            visited[nxtfinish] = 1;
            backtrack2(nxtfinish, mid, start);
            visited[nxtfinish] = 0;
        }
    }

    void backtrack(ll mid, ll start) {
        if (mid != start) {
            backtrack2(mid, mid, start);
        }

        for(int nxtmid : GR[mid]) {
            if (visited[nxtmid]) continue;
            visited[nxtmid] = 1;
            backtrack(nxtmid, start);
            visited[nxtmid] = 0;
        }
    }

    void preprocess() {
        N = inN;
        M = inM;
        for(int i = 1; i <= N; ++i) GR[i] = inGR[i];
    }

    void solve() {
        for(int i = 1; i <= N; ++i) {
            visited[i] = 1;
            backtrack(i, i);
            visited[i] = 0;
        }

        for(int i = 1; i <= N; ++i) {
            for(int j = 1; j <= N; ++j) {
                for(int k = 1; k <= N; ++k) {
                    ans += havepath[i][j][k];
                }
            }
        }

        cout << ans << endl;
    }

    void process() {
        preprocess();
        solve();
    }
}

namespace subtask3 {
    int N, M, CpnCnt, cpn[100007], sz[100007], type[100007];
    vector<int> GR[100007];

    void preprocess() {
        N = inN;
        M = inM;
        for(int i = 1; i <= N; ++i) GR[i] = inGR[i];
    }

    void Dfs(ll u, ll last) {
        cpn[u] = CpnCnt;
        for(int v : GR[u]) {
            if (v == last) continue;
            if (!cpn[v]) Dfs(v, u);
            else type[CpnCnt] = 1;
        }
    }

    void solve() {
        for(int i = 1; i <= N; ++i) {
            if (!cpn[i]) {
                CpnCnt++;
                Dfs(i, 0);
            }
        }

        for(int i = 1; i <= N; ++i) {
            sz[cpn[i]]++;
        }

        ll ans = 0;

        for(int i = 1; i <= CpnCnt; ++i) {
            ll k = sz[i];
            //cerr << i << " " << k << endl;
            if (!type[i]) ans += (k * (k - 1) * (k - 2)) / 6;
            else ans += ((k - 1) * (k - 2)) / 2 * k;
        }

        cout << ans * 2;
    }

    void process() {
        preprocess();
        solve();
    }
}

namespace subtask5 {
    int N, M;
    vector<int> GR[100007];
    int visited[100007], sz[100007];
    ll ans = 0;

    void Dfs(int u) {
        visited[u] = 1;
        for(int v : GR[u]) {
            if (visited[v]) continue;
            Dfs(v);
            sz[u] += sz[v];
        }
        sz[u]++;
    }

    void Dfs2(int u, int last, int root) {
        //cerr << u << " " << (sz[root] - sz[u]) << " " << (sz[u] - 1) << endl;
        ans += (sz[root] - sz[u]) * (sz[u] - 1);
        for(int v : GR[u]) {
            if (v == last) continue;
            Dfs2(v, u, root);
        }
    }

    void preprocess() {
        N = inN;
        M = inM;
        for(int i = 1; i <= N; ++i) GR[i] = inGR[i];
    }

    void solve() {
        for(int i = 1; i <= N; ++i) {
            if (!visited[i]) {
                Dfs(i);
                Dfs2(i, 0, i);
            }
        }

//        for(int i = 1; i <= N; ++i) {
//            cerr << i << " " << sz[i] << endl;
//        }

        cout << ans * 2;
    }

    void process() {
        preprocess();
        solve();
    }
}

int main() {
    initialize();

    subtask5 :: process();

//    cout << 10 << " " << (100 * 99) / 2 << endl;
//    for(int i = 1; i <= 100; ++i) {
//        for(int j = 1; j <= i - 1; ++j) {
//            cout << i << " " << j << endl;
//        }
//    }
}

Compilation message (stderr)

count_triplets.cpp: In function 'void initialize()':
count_triplets.cpp:13:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   13 |         freopen("FILE.INP", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
count_triplets.cpp:14:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   14 |         freopen("FILE.OUT", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
count_triplets.cpp: In function 'int type_determine()':
count_triplets.cpp:28:1: warning: control reaches end of non-void function [-Wreturn-type]
   28 | }
      | ^

• Subtask 1: 0 / 5
• Subtask 2: 0 / 11
• Subtask 3: 0 / 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