oj.uz

Submission #699625

# Submission time Handle Problem Language Result Execution time Memory
699625 2023-02-17T14:55:22 Z finn__ Duathlon (APIO18_duathlon) C++17
0 / 100
 79 ms 27064 KB 
#include <bits/stdc++.h>
using namespace std;

#define N 200000

vector<unsigned> g[N], bccg[N];
unsigned y[N], l[N], subtree_size[N], s[N];
bitset<N> visited;
size_t n, m, t = 0, n_bcc;

unsigned build_bcc_tree(unsigned u, unsigned p = -1, unsigned i = 0)
{
    y[u] = l[u] = i++;
    visited[u] = 1;
    s[t++] = u;

    for (unsigned const &v : g[u])
    {
        if (!visited[v])
        {
            i = build_bcc_tree(v, u, i);
            l[u] = min(l[u], l[v]);

            if (l[v] >= y[u])
            {
                // Collect all nodes in the BCC of u and v. u is an articulation
                // point, so leave it in the stack.
                bccg[u].push_back(n_bcc);
                while (s[t] != v)
                    bccg[n_bcc].push_back(s[--t]);
                n_bcc++;
            }
        }
        else if (v != p)
            l[u] = min(l[u], y[v]);
    }

    return i;
}

// The BCC graph is bipartite with BCCs in one partition and original nodes in
// the other.
uint64_t get_bad_triples(unsigned u, unsigned p = -1)
{
    uint64_t ans = 0;
    subtree_size[u] = u < n;
    for (unsigned const &v : bccg[u])
    {
        if (v != p)
        {
            ans += get_bad_triples(v, u);
            subtree_size[u] += subtree_size[v];
            if (v < n)
                ans += bccg[u].size() * subtree_size[v] * (subtree_size[v] - 1);
        }
    }

    if (u >= n) // Add the contribution with the pair (s, f) outside u's subtree.
        ans += bccg[u].size() * (n - subtree_size[u]) * (n - subtree_size[u] - 1);
    return ans;
}

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

    for (size_t i = 0; i < m; i++)
    {
        unsigned u, v;
        scanf("%u %u", &u, &v);
        g[u - 1].push_back(v - 1);
        g[v - 1].push_back(u - 1);
    }

    unsigned long long ans = 0;
    for (size_t i = 0; i < n; i++)
        if (!visited[i])
        {
            build_bcc_tree(i);
            ans -= get_bad_triples(i);
            ans += subtree_size[i] * (subtree_size[i] - 1) * (subtree_size[i] - 2);
        }

    printf("%llu\n", ans);
}

Compilation message

count_triplets.cpp: In function 'int main()':
count_triplets.cpp:65:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   65 |     scanf("%zu %zu", &n, &m);
      |     ~~~~~^~~~~~~~~~~~~~~~~~~
count_triplets.cpp:71:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   71 |         scanf("%u %u", &u, &v);
      |         ~~~~~^~~~~~~~~~~~~~~~~

Subtask #1
0 / 5.0

# Verdict Execution time Memory Grader output
1 Incorrect 5 ms 9684 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #2
0 / 11.0

# Verdict Execution time Memory Grader output
1 Incorrect 5 ms 9684 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #3
0 / 8.0

# Verdict Execution time Memory Grader output
1 Incorrect 79 ms 27064 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #4
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 9812 KB Output is correct
2 Correct 6 ms 9900 KB Output is correct
3 Correct 5 ms 9824 KB Output is correct
4 Correct 6 ms 9940 KB Output is correct
5 Correct 6 ms 9836 KB Output is correct
6 Correct 6 ms 9812 KB Output is correct
7 Correct 5 ms 9812 KB Output is correct
8 Correct 5 ms 9812 KB Output is correct
9 Correct 5 ms 9812 KB Output is correct
10 Incorrect 6 ms 9708 KB Output isn't correct
11 Halted 0 ms 0 KB -

Subtask #5
0 / 13.0

# Verdict Execution time Memory Grader output
1 Incorrect 72 ms 20452 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #6
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 9812 KB Output is correct
2 Correct 6 ms 9732 KB Output is correct
3 Correct 5 ms 9712 KB Output is correct
4 Correct 6 ms 9812 KB Output is correct
5 Correct 6 ms 9708 KB Output is correct
6 Correct 6 ms 9804 KB Output is correct
7 Correct 6 ms 9684 KB Output is correct
8 Correct 8 ms 9712 KB Output is correct
9 Correct 6 ms 9772 KB Output is correct
10 Correct 6 ms 9684 KB Output is correct
11 Correct 5 ms 9812 KB Output is correct
12 Correct 6 ms 9812 KB Output is correct
13 Correct 5 ms 9812 KB Output is correct
14 Correct 6 ms 9812 KB Output is correct
15 Correct 6 ms 9832 KB Output is correct
16 Incorrect 6 ms 9712 KB Output isn't correct
17 Halted 0 ms 0 KB -

Subtask #7
0 / 20.0

# Verdict Execution time Memory Grader output
1 Incorrect 77 ms 20556 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #8
0 / 8.0

# Verdict Execution time Memory Grader output
1 Incorrect 5 ms 9684 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #9
0 / 10.0

# Verdict Execution time Memory Grader output
1 Incorrect 5 ms 9684 KB Output isn't correct
2 Halted 0 ms 0 KB -