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Submission #484795

# Submission time Handle Problem Language Result Execution time Memory
484795 2021-11-05T13:36:51 Z Victor Pipes (CEOI15_pipes) C++17
100 / 100
 934 ms 15172 KB 
#include <bits/stdc++.h>

using namespace std;

#define rep(i, a, b) for (int i = (a); i < (b); ++i)
#define per(i, a, b) for (int i = (b - 1); i >= (a); --i)
#define trav(a, x) for (auto &a : x)

#define all(x) x.begin(), x.end()
#define sz(x) x.size()
#define pb push_back
#define debug(x) cout << #x << " = " << x << endl

#define umap unordered_map
#define uset unordered_set

typedef pair<int, int> ii;
typedef pair<int, ii> iii;
typedef vector<int> vi;
typedef vector<ii> vii;
typedef vector<vi> vvi;

typedef long long ll;
typedef pair<ll, ll> pll;
typedef vector<ll> vll;
typedef vector<pll> vpll;

const int INF = 1'000'000'007;

struct union_find {
    int p[100001];
    char rank[100001];
    union_find(int n) {
        rep(i, 0, n) p[i] = i;
        memset(rank, 0, sizeof(rank));
    }

    int find_set(int i) { return p[i] == i ? i : p[i] = find_set(p[i]); }
    bool same(int i, int j) { return find_set(i) == find_set(j); }
    void union_set(int i, int j) {
        i = find_set(i);
        j = find_set(j);
        if (i == j) return;

        if (rank[i] < rank[j]) swap(i, j);
        if (rank[i] == rank[j]) ++rank[i];
        p[j] = i;
    }
};

int dfs_num[100001], dfs_lo[100001], cnt = 0;
vi graph[100001];

void dfs(int u, int p) {
    dfs_num[u] = dfs_lo[u] = cnt++;
    trav(v, graph[u])  {
        if (dfs_num[v] == -1) {
            dfs(v, u);
            if (dfs_num[u] < dfs_lo[v]) cout << u + 1 << ' ' << v + 1 << endl;
            dfs_lo[u] = min(dfs_lo[u], dfs_lo[v]);
        }

        else if (v != p)
            dfs_lo[u] = min(dfs_lo[u], dfs_num[v]);

        else p=-1;
    }
}

int main() {
    cin.tie(0)->sync_with_stdio(0);
    cin.exceptions(cin.failbit);

    memset(dfs_num, -1, sizeof(dfs_num));
    int n, m, u, v;
    cin >> n >> m;
    union_find uf1(n), uf2(n);

    rep(i, 0, m) {
        cin >> u >> v;
        --u;
        --v;

        if(uf1.same(u,v)&&uf2.same(u,v))continue;

        if (uf1.same(u, v)) {
            uf2.union_set(u, v);
            graph[u].pb(v);
            graph[v].pb(u);
        }

        else {
            uf1.union_set(u, v);
            graph[u].pb(v);
            graph[v].pb(u);
        }
    }

    rep(i, 0, n) {
        if (dfs_num[i] != -1) continue;
        cnt = 0;
        dfs(i,i);
    }
    return 0;
}

Subtask #1
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 3916 KB Output is correct
2 Correct 2 ms 3916 KB Output is correct

Subtask #2
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 4416 KB Output is correct
2 Correct 6 ms 4304 KB Output is correct

Subtask #3
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 85 ms 4296 KB Output is correct
2 Correct 80 ms 4172 KB Output is correct

Subtask #4
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 138 ms 5056 KB Output is correct
2 Correct 167 ms 4672 KB Output is correct

Subtask #5
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 245 ms 6636 KB Output is correct
2 Correct 222 ms 7188 KB Output is correct

Subtask #6
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 312 ms 11844 KB Output is correct
2 Correct 301 ms 8832 KB Output is correct

Subtask #7
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 520 ms 12900 KB Output is correct
2 Correct 449 ms 10776 KB Output is correct

Subtask #8
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 656 ms 15068 KB Output is correct
2 Correct 602 ms 9804 KB Output is correct

Subtask #9
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 785 ms 15172 KB Output is correct
2 Correct 759 ms 9696 KB Output is correct

Subtask #10
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 934 ms 14532 KB Output is correct
2 Correct 889 ms 11804 KB Output is correct