Submission #152952

#	Time	Username	Problem	Language	Result	Execution time	Memory
152952		arnold518	Duathlon (APIO18_duathlon)	C++14	23 / 100	1112 ms	1048580 KiB

count_triplets

#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;

const int MAXN = 1e5;

int N, M;
vector<int> adj[MAXN+10];

ll ans=0;
int sz[MAXN+10];
bool vis[MAXN+10];

void dfs1(int now, int bef)
{
    sz[now]=1; vis[now]=1;
    for(int nxt : adj[now])
    {
        if(nxt==bef) continue;
        dfs1(nxt, now);
        sz[now]+=sz[nxt];
    }
}

void dfs2(int now, int bef)
{
    int sum=0;
    for(int nxt : adj[now])
    {
        if(nxt==bef) continue;
        sz[now]-=sz[nxt];
        sz[nxt]+=sz[now];
        dfs2(nxt, now);
        sz[nxt]-=sz[now];
        sz[now]+=sz[nxt];
    }
    for(int nxt : adj[now])
    {
        ans-=(ll)sz[nxt]*sz[nxt];
        sum+=sz[nxt];
    }
    ans+=(ll)sum*sum;
}

int main()
{
    int i, j;

    scanf("%d%d", &N, &M);
    for(i=1; i<=M; i++)
    {
        int u, v;
        scanf("%d%d", &u, &v);
        adj[u].push_back(v);
        adj[v].push_back(u);
    }

    for(i=1; i<=N; i++) if(!vis[i])
    {
        dfs1(i, i);
        dfs2(i, i);
    }
    printf("%lld", ans);
}

Compilation message (stderr)

count_triplets.cpp: In function 'int main()':
count_triplets.cpp:50:12: warning: unused variable 'j' [-Wunused-variable]
     int i, j;
            ^
count_triplets.cpp:52:10: 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:56:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d%d", &u, &v);
         ~~~~~^~~~~~~~~~~~~~~~

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