제출 #159009

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
159009		arnold518	철인 이종 경기 (APIO18_duathlon)	C++14	10 / 100	162 ms	38796 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];

int idx[MAXN+10], low[MAXN+10], cnt;
ll ans;

void dfs(int now, int bef)
{
    idx[now]=low[now]=++cnt;
    for(auto nxt : adj[now])
    {
        if(nxt==bef) continue;
        if(!idx[nxt])
        {
            dfs(nxt, now);
            low[now]=min(low[now], low[nxt]);
        }
        else
        {
            low[now]=min(low[now], idx[nxt]);
        }
    }
}

bool vis[MAXN+10];
int sz[2*MAXN+10];
vector<int> bcc[MAXN+10], adj2[MAXN+10];
int ccnt;

void color(int now, int col)
{
    if(col)
    {
        bcc[now].push_back(col);
        sz[col]++;
    }
    vis[now]=true;

    for(int nxt : adj[now])
    {
        if(vis[nxt]) continue;
        if(idx[now]<=low[nxt])
        {
            ccnt++;
            bcc[now].push_back(ccnt);
            sz[ccnt]++;
            color(nxt, ccnt);
        }
        else
        {
            color(nxt, col);
        }
    }
}

bool vis2[2*MAXN+10];
void dfs2(int now)
{
    vis2[now]=true;
    for(auto nxt : adj2[now])
    {
        if(vis2[nxt]) continue;
        dfs2(nxt);
        sz[now]+=sz[nxt];
    }
    //printf("!%d %d\n", now, sz[now]);
}

void dfs3(int now, int bef)
{
    ll sum=0, val=0;
    for(int nxt : adj2[now])
    {
        if(nxt==bef) continue;
        sz[now]-=sz[nxt];
        sz[nxt]+=sz[now];
        dfs3(nxt, now);
        sz[nxt]-=sz[now];
        sz[now]+=sz[nxt];
    }
    for(int nxt : adj2[now])
    {
        val-=(ll)sz[nxt]*sz[nxt];
        sum+=sz[nxt];
        //printf("!!!!%d / %d %d\n", now, nxt, sz[nxt]);
    }
    val+=sum*sum;
    //printf("%d %lld %lld\n", now, val, sum);
    if(now>N) ans+=val;
    else ans+=(sz[now]-sum)*val+2*(sz[now]-sum)*((sum-adj2[now].size())*(sz[now]-sum-1)+(sum-adj2[now].size())*(adj2[now].size()-1));//, printf("WOW %d %lld %lld\n", now, (sz[now]-sum)*val, 2*(sz[now]-sum)*((sum-adj2[now].size())*(sz[now]-sum-1)+(sum-adj2[now].size())*(adj2[now].size()-1)));
}

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]) continue;
        dfs(i, i);
        color(i, 0);
    }
    for(i=1; i<=N; i++)
    {
        if(bcc[i].size()>1)
        {
            for(auto j : bcc[i]) adj2[i+N].push_back(j), adj2[j].push_back(i+N);
            sz[i+N]=1;
        }
    }
    for(i=1; i<=ccnt; i++) ans+=(ll)(sz[i])*(sz[i]-1)*(sz[i]-2); //printf("ANS %lld\n", ans);
    for(i=1; i<=ccnt; i++) sz[i]-=adj2[i].size();
/*
    for(i=1; i<=2*N; i++)
    {
        printf("%d : (%d)", i, sz[i]);
        for(auto j : adj2[i]) printf("%d ", j);
        printf("\n");
    }
*/
    for(i=1; i<=ccnt; i++)
    {
        if(vis2[i]) continue;
        dfs2(i);
        dfs3(i, i);
    }
    printf("%lld", ans);
}

컴파일 시 표준 에러 (stderr) 메시지

count_triplets.cpp: In function 'int main()':
count_triplets.cpp:104:12: warning: unused variable 'j' [-Wunused-variable]
     int i, j;
            ^
count_triplets.cpp:106:10: 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:110:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d%d", &u, &v);
         ~~~~~^~~~~~~~~~~~~~~~

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