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Submission #873187

# Submission time Handle Problem Language Result Execution time Memory
873187 2023-11-14T15:30:34 Z Ghulam_Junaid Pipes (CEOI15_pipes) C++17
100 / 100
 907 ms 14400 KB 
#include <bits/stdc++.h>
using namespace std;

const int N = 1e5 + 1;
int n, m, h[N], mnh[N], edges, u, v, i;
bool vis[N];
vector<pair<int, int>> g[N];

int root1(int& v){
    return (h[v] == -1 ? v : h[v] = root1(h[v]));
}

int root2(int& v){
    return (mnh[v] == -1 ? v : mnh[v] = root2(mnh[v]));
}

void merge1(int& u, int& v){    
    int r1 = root1(v);
    int r2 = root1(u);

    h[r1] = r2;

    edges++;
    g[v].push_back({u, edges});
    g[u].push_back({v, edges});
}

void merge2(int& u, int& v){
    int r1 = root2(u);
    int r2 = root2(v);

    if (r1 == r2)
        return;

    mnh[r1] = r2;

    edges++;
    g[v].push_back({u, edges});
    g[u].push_back({v, edges});
}

void dfs(int& v, pair<int, int> prev = {-1, -1}){
    vis[v] = 1;
    if (prev.first == -1)
        h[v] = 0;
    mnh[v] = h[v];

    for (auto& [u, id] : g[v]){
         if (prev.first == u and prev.second == id)
            continue;

        mnh[v] = min(mnh[v], h[u]);

        if (vis[u])
            continue;

        h[u] = h[v] + 1;
        dfs(u, {v, id});
        mnh[v] = min(mnh[v], mnh[u]);

        if (mnh[u] >= h[u])
            printf("%d %d\n", u, v);
            
    }
}

int main(){

    scanf("%d%d", &n, &m);

    for (i=1; i<=n; i++)
        h[i] = mnh[i] = -1;

    for (i=0; i<m; i++){
        scanf("%d%d", &u, &v);

        if (root1(u) != root1(v))
            merge1(u, v);
        else if (root2(u) != root2(v))
            merge2(u, v);
    }

    for (i=1; i<=n; i++)
        h[i] = mnh[i] = n + 100;

    for (v = 1; v <= n; v++)
        if (!vis[v])
            dfs(v);
}

Compilation message

pipes.cpp: In function 'int main()':
pipes.cpp:69:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   69 |     scanf("%d%d", &n, &m);
      |     ~~~~~^~~~~~~~~~~~~~~~
pipes.cpp:75:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   75 |         scanf("%d%d", &u, &v);
      |         ~~~~~^~~~~~~~~~~~~~~~

Subtask #1
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 2648 KB Output is correct
2 Correct 1 ms 2652 KB Output is correct

Subtask #2
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 3164 KB Output is correct
2 Correct 4 ms 2904 KB Output is correct

Subtask #3
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 82 ms 3028 KB Output is correct
2 Correct 81 ms 2908 KB Output is correct

Subtask #4
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 132 ms 3684 KB Output is correct
2 Correct 195 ms 3432 KB Output is correct

Subtask #5
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 239 ms 5308 KB Output is correct
2 Correct 196 ms 5056 KB Output is correct

Subtask #6
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 296 ms 10824 KB Output is correct
2 Correct 295 ms 8020 KB Output is correct

Subtask #7
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 507 ms 12228 KB Output is correct
2 Correct 443 ms 8696 KB Output is correct

Subtask #8
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 598 ms 14344 KB Output is correct
2 Correct 606 ms 10348 KB Output is correct

Subtask #9
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 750 ms 14400 KB Output is correct
2 Correct 686 ms 10328 KB Output is correct

Subtask #10
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 870 ms 13808 KB Output is correct
2 Correct 907 ms 10584 KB Output is correct