Submission #1234234

#	Time	Username	Problem	Language	Result	Execution time	Memory
1234234		Jer	Duathlon (APIO18_duathlon)	C++20	0 / 100	1115 ms	1114112 KiB

count_triplets

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;

const int MAXN = 100005;
vector<int> con[MAXN];
vector<int> parent(MAXN, 0);
vector<int> depth(MAXN, 0);

void find_depth(int curr, int par, int d)
{
    parent[curr] = par;
    depth[curr] = d;
    for (auto i : con[curr])
    {
        if (i == par)
            continue;
        find_depth(i, curr, d + 1);
    }
}

int lca(int u, int v)
{
    while (depth[u] > depth[v])
        u = parent[u];

    while (depth[v] > depth[u])
        v = parent[v];

    while (u != v)
    {
        u = parent[u];
        v = parent[v];
    }

    return u;
}

int distance(int u, int v)
{
    int l = lca(u, v);
    return depth[u] + depth[v] - 2 * depth[l];
}

int n, m;

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

    int a, b;
    for (int i = 0; i < m; i++)
        scanf("%d%d", &a, &b), con[a].push_back(b), con[b].push_back(a);

    find_depth(1, 1, 0);

    ll res = 0;
    for (int i = 1; i <= n; i++)
        for (int j = 1; j <= n; j++)
        {
            int dist = distance(i, j);
            if (dist >= 2)
                res += dist - 1;
        }

    printf("%lld\n", res);

    return 0;
}

Compilation message (stderr)

count_triplets.cpp: In function 'int main()':
count_triplets.cpp:51:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   51 |     scanf("%d%d", &n, &m);
      |     ~~~~~^~~~~~~~~~~~~~~~
count_triplets.cpp:55:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   55 |         scanf("%d%d", &a, &b), con[a].push_back(b), con[b].push_back(a);
      |         ~~~~~^~~~~~~~~~~~~~~~

• Subtask 1: 0 / 5
• Subtask 2: 0 / 11
• Subtask 3: 0 / 8
• Subtask 4: 0 / 10
• Subtask 5: 0 / 13
• Subtask 6: 0 / 15
• Subtask 7: 0 / 20
• Subtask 8: 0 / 8
• Subtask 9: 0 / 10