제출 #1113436

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
1113436		adaawf	철인 이종 경기 (APIO18_duathlon)	C++17	0 / 100	72 ms	20872 KiB

count_triplets

#include <iostream>
#include <vector>
using namespace std;
pair<int, int> e[200005];
vector<pair<int, int>> g[100005];
long long int dd[100005], a[100005], b[100005], tin[100005], f[100005], s[100005], z = 0;
vector<int> gg[100005], v;
void dfs(int x, int p) {
    tin[x] = f[x] = ++z;
    for (auto w : g[x]) {
        if (w.first == p) continue;
        if (tin[w.first]) {
            f[x] = min(f[x], tin[w.first]);
        }
        else {
            dfs(w.first, x);
            f[x] = min(f[x], f[w.first]);
            if (tin[x] < f[w.first]) {
                dd[w.second] = 1;
            }
        }
    }
}
void dfs2(int x, int h) {
    b[x] = h;
    a[h]++;
    for (auto w : g[x]) {
        if (b[w.first] || dd[w.second]) continue;
        dfs2(w.first, h);
    }
}
long long int res = 0, d = 0;
void dfs3(int x, int p) {
    v.push_back(x);
    s[x] = a[x];
    d += a[x];
    tin[x] = 1;
    long long int h = 0;
    for (int w : gg[x]) {
        if (w == p) continue;
        dfs3(w, x);
        s[x] += s[w];
    }
}
void dfs4(int x, int p) {
    long long int h = 0;
    for (int w : gg[x]) {
        long long int k;
        if (w == p) {
            k = d - s[x];
        }
        else {
            dfs4(w, x);
            k = s[w];
        }
        res += h * k;
        h += k;
    }
}
int main() {
    ios::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    int n, m;
    cin >> n >> m;
    for (int i = 1; i <= m; i++) {
        int u, v;
        cin >> u >> v;
        e[i] = {u, v};
        g[u].push_back({v, i});
        g[v].push_back({u, i});
    }
    for (int i = 1; i <= n; i++) {
        if (tin[i] == 0) {
            dfs(i, -1);
        }
    }
    z = 0;
    for (int i = 1; i <= n; i++) {
        if (b[i] == 0) {
            z++;
            dfs2(i, z);
        }
    }
    for (int i = 1; i <= m; i++) {
        if (dd[i] == 1) {
            gg[b[e[i].first]].push_back(b[e[i].second]);
            gg[b[e[i].second]].push_back(b[e[i].first]);
        }
    }
    for (int i = 1; i <= z; i++) tin[i] = 0;
    for (int i = 1; i <= z; i++) {
        if (tin[i] == 0) {
            v.clear();
            d = 0;
            dfs3(i, -1);
            dfs4(i, -1);
            for (int w : v) {
                //cout << w << " " << a[w] << " " << s[w] << '\n';
                res += (a[w] - 1) * a[w] * a[w] / 2;
                res += d - a[w];
                res += (a[w] - 1) * a[w] * (d - a[w]);
            }
        }
    }
    cout << (res - n * (n - 1)) * 2;
}

컴파일 시 표준 에러 (stderr) 메시지

count_triplets.cpp: In function 'void dfs3(int, int)':
count_triplets.cpp:38:19: warning: unused variable 'h' [-Wunused-variable]
   38 |     long long int h = 0;
      |                   ^

• 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