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Submission #1021685

# Submission time Handle Problem Language Result Execution time Memory
1021685 2024-07-13T02:32:01 Z idiotcomputer Pipes (CEOI15_pipes) C++11
50 / 100
 878 ms 65536 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;
    }
};

constexpr size_t N = 100000;

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

pair<unsigned, unsigned> find_bridges(unsigned u, unsigned p, unsigned i)
{
    unsigned lu = y[u] = ++i;
    bool parent_seen = 0;

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

    return make_pair(i, lu);
}

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.merge(u, v) || d2.merge(u, v))
        {
            g[u].push_back(v);
            g[v].push_back(u);
        }
    }

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

Compilation message

pipes.cpp: In function 'int main()':
pipes.cpp:58:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   58 |     scanf("%zu %zu", &n, &m);
      |     ~~~~~^~~~~~~~~~~~~~~~~~~
pipes.cpp:65:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   65 |         scanf("%u %u", &u, &v);
      |         ~~~~~^~~~~~~~~~~~~~~~~

Subtask #1
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 2652 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 3 ms 3164 KB Output is correct
2 Correct 5 ms 3064 KB Output is correct

Subtask #3
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 71 ms 3152 KB Output is correct
2 Correct 106 ms 2932 KB Output is correct

Subtask #4
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 126 ms 3760 KB Output is correct
2 Correct 137 ms 3224 KB Output is correct

Subtask #5
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 210 ms 5208 KB Output is correct
2 Correct 167 ms 4940 KB Output is correct

Subtask #6
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 317 ms 10328 KB Output is correct
2 Runtime error 246 ms 25040 KB Memory limit exceeded
3 Halted 0 ms 0 KB -

Subtask #7
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 422 ms 11500 KB Output is correct
2 Runtime error 413 ms 42068 KB Memory limit exceeded
3 Halted 0 ms 0 KB -

Subtask #8
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 541 ms 13716 KB Output is correct
2 Runtime error 576 ms 49972 KB Memory limit exceeded
3 Halted 0 ms 0 KB -

Subtask #9
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 658 ms 13648 KB Output is correct
2 Runtime error 743 ms 61604 KB Memory limit exceeded
3 Halted 0 ms 0 KB -

Subtask #10
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 863 ms 13140 KB Output is correct
2 Runtime error 878 ms 65536 KB Memory limit exceeded
3 Halted 0 ms 0 KB -