Submission #49631

#	Time	Username	Problem	Language	Result	Execution time	Memory
49631		SpaimaCarpatilor	Duathlon (APIO18_duathlon)	C++17	0 / 100	297 ms	29600 KiB

count_triplets

#include<bits/stdc++.h>

using namespace std;

int nodes, N, M, lev[100009], dp[100009], vol[200009], papa[200009];
long long sumProd[200009];
stack < pair < int, int > > stk;
vector < int > v[100009], h[200009];

void addComp (pair < int, int > whenToStop)
{
    pair < int, int > curr;
    vector < int > currComp;
    do {
        curr = stk.top ();
        stk.pop ();
        currComp.push_back (curr.first);
        currComp.push_back (curr.second);
    }while (curr != whenToStop);
    sort (currComp.begin (), currComp.end ());
    currComp.erase (unique (currComp.begin (), currComp.end ()), currComp.end ());
/*    for (auto it : currComp)
        printf ("%d ", it);
    printf ("\n");*/
    nodes ++;
    for (auto it : currComp)
        h[it].push_back (nodes),
        h[nodes].push_back (it);
}

void dfs (int nod, int tata)
{
    dp[nod] = lev[nod];
    for (auto it : v[nod])
        if (lev[it] == 0)
        {
            lev[it] = lev[nod] + 1;
            stk.push ({it, nod});
            dfs (it, nod);
            if (dp[it] < dp[nod])
                dp[nod] = dp[it];
            if (dp[it] >= lev[nod])
                addComp ({it, nod});
        }
    for (auto it : v[nod])
        if (it != tata)
        {
            if (lev[it] < dp[nod])
                dp[nod] = lev[it];
        }
}

void init (int nod, int tata)
{
    vol[nod] = (nod <= N), papa[nod] = tata;
    int sum = 0;
    for (auto it : h[nod])
        if (it != tata)
            init (it, nod), vol[nod] += vol[it],
            sumProd[nod] += 1LL * sum * vol[it],
            sum += vol[it];
    sumProd[nod] += 1LL * sum * (N - vol[nod]);
    sumProd[nod] <<= 1LL;
}

int main ()
{
//freopen ("input", "r", stdin);
//freopen ("output", "w", stdout);

scanf ("%d %d", &N, &M);
while (M --)
{
    int x, y;
    scanf ("%d %d", &x, &y);
    v[x].push_back (y);
    v[y].push_back (x);
}
lev[1] = 1, nodes = N;
dfs (1, -1), init (1, -1);
long long ans = 0;
for (int x=1; x<=N; x++)
{
    ans += sumProd[x];
    for (auto comp : h[x])
    {
        ans += sumProd[comp];
        if (papa[comp] == x)
            ans -= 2LL * (N - vol[comp]) * vol[comp];
        else
            ans -= 2LL * (N - vol[x]) * vol[x];
    }
}
printf ("%lld\n", ans);
return 0;
}

Compilation message (stderr)

count_triplets.cpp: In function 'int main()':
count_triplets.cpp:71:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
 scanf ("%d %d", &N, &M);
 ~~~~~~^~~~~~~~~~~~~~~~~
count_triplets.cpp:75:11: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf ("%d %d", &x, &y);
     ~~~~~~^~~~~~~~~~~~~~~~~

• 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