oj.uz

Submission #706735

# Submission time Handle Problem Language Result Execution time Memory
706735 2023-03-07T15:38:08 Z finn__ Pipes (CEOI15_pipes) C++17
20 / 100
 1220 ms 13580 KB 
#include <bits/stdc++.h>
using namespace std;

struct Dsu
{
    vector<int> p;

    Dsu(size_t n) { p = vector<int>(n, -1); }

    int repr(int u) { return p[u] < 0 ? u : p[u] = repr(p[u]); }

    bool merge(int i, int j)
    {
        i = repr(i);
        j = repr(j);
        if (i == j)
            return 0;

        if (p[i] > p[j])
            swap(i, j);
        p[i] += p[j];
        p[j] = i;
        return 1;
    }

    bool same_set(int i, int j) { return repr(i) == repr(j); }

    int set_size(int i) { return -p[repr(i)]; }
};

constexpr size_t N = 100000;

vector<unsigned> g[N];
unsigned y[N];
bitset<N> visited;

pair<unsigned, unsigned> find_bridges(unsigned u, unsigned p, unsigned i)
{
    unsigned l = y[u] = i++;
    visited[u] = 1;

    for (unsigned const &v : g[u])
    {
        if (!visited[v])
        {
            unsigned lv;
            tie(i, lv) = find_bridges(v, u, i);
            l = min(l, lv);
            if (lv > y[u])
                printf("%u %u\n", u + 1, v + 1);
        }
        else if (v != p)
            l = min(l, y[v]);
    }

    return make_pair(i, l);
}

int main()
{
    size_t n, m;
    scanf("%zu %zu", &n, &m);

    Dsu d1(n), d2(n);

    while (m--)
    {
        unsigned u, v;
        scanf("%u %u", &u, &v);
        u--, v--;
        if (!d1.same_set(u, v))
            d1.merge(u, v), g[u].push_back(v), g[v].push_back(u);
        else if (!d2.same_set(u, v))
            d2.merge(u, v), g[u].push_back(v), g[v].push_back(u);
    }

    for (unsigned i = 0; i < n; i++)
        if (!visited[i])
            find_bridges(i, UINT_MAX, 0);
}

Compilation message

pipes.cpp: In function 'int main()':
pipes.cpp:62:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   62 |     scanf("%zu %zu", &n, &m);
      |     ~~~~~^~~~~~~~~~~~~~~~~~~
pipes.cpp:69:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   69 |         scanf("%u %u", &u, &v);
      |         ~~~~~^~~~~~~~~~~~~~~~~

Subtask #1
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 2644 KB Output is correct
2 Incorrect 2 ms 2644 KB Wrong number of edges
3 Halted 0 ms 0 KB -

Subtask #2
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 3028 KB Output is correct
2 Incorrect 5 ms 2900 KB Wrong number of edges
3 Halted 0 ms 0 KB -

Subtask #3
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 110 ms 2936 KB Output is correct
2 Incorrect 111 ms 2796 KB Wrong number of edges
3 Halted 0 ms 0 KB -

Subtask #4
0 / 10.0

# Verdict Execution time Memory Grader output
1 Incorrect 208 ms 3608 KB Wrong number of edges
2 Halted 0 ms 0 KB -

Subtask #5
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 317 ms 5188 KB Output is correct
2 Correct 248 ms 4936 KB Output is correct

Subtask #6
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 383 ms 10244 KB Output is correct
2 Incorrect 401 ms 6780 KB Wrong number of edges
3 Halted 0 ms 0 KB -

Subtask #7
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 601 ms 11492 KB Output is correct
2 Incorrect 604 ms 8588 KB Wrong number of edges
3 Halted 0 ms 0 KB -

Subtask #8
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 812 ms 13572 KB Output is correct
2 Incorrect 748 ms 8712 KB Wrong number of edges
3 Halted 0 ms 0 KB -

Subtask #9
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 988 ms 13580 KB Output is correct
2 Incorrect 936 ms 8592 KB Wrong number of edges
3 Halted 0 ms 0 KB -

Subtask #10
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1220 ms 12940 KB Output is correct
2 Correct 1168 ms 10092 KB Output is correct