Submission #745942

#	Time	Username	Problem	Language	Result	Execution time	Memory
745942		bgnbvnbv	Cijanobakterije (COCI21_cijanobakterije)	C++14	70 / 70	100 ms	21096 KiB

Main

#include<bits/stdc++.h>
#define TASKNAME "codeforce"
#define pb push_back
#define pli pair<int,int>
#define fi first
#define se second
#define fastio ios_base::sync_with_stdio(false); cin.tie(NULL);
using namespace std;
using ll=long long;
const ll maxN=2e5;
const ll inf=1e18;
const ll mod=1e9+7;
ll h[maxN];
ll lab[maxN];
vector<ll>vec[maxN],g[maxN];
ll findset(ll x)
{
    return lab[x]<0?x:lab[x]=findset(lab[x]);
}
void unite(ll u,ll v)
{
    u=findset(u);
    v=findset(v);
    if(u==v) return;
    if(lab[u]>lab[v]) swap(u,v);
    lab[u]+=lab[v];
    lab[v]=u;
    for(auto zz:vec[v]) vec[u].pb(zz);
    vec[v].clear();
}
void dfs(ll u,ll p)
{
    for(int v:g[u])
    {
        if(v!=p)
        {
            h[v]=h[u]+1;
            dfs(v,u);
        }
    }
}
ll ans=0;
ll m;
ll n;
void solve()
{
    cin >> n >> m;
    for(int i=1;i<=n;i++) lab[i]=-1,vec[i].pb(i);
    for(int i=1;i<=m;i++)
    {
        ll u,v;
        cin >> u >> v;
        g[u].pb(v);
        g[v].pb(u);
        unite(u,v);
    }
    for(int i=1;i<=n;i++)
    {
        if(findset(i)==i)
        {
            dfs(i,0);
            ll mx=-1,id=-1;
            h[i]=0;
            for(auto zz:vec[i])
            {
                if(h[zz]>mx)
                {
                    mx=h[zz];
                    id=zz;
                }
            }
            h[id]=0;
            dfs(id,0);
            mx=-1;
            for(auto zz:vec[i])
            {
                mx=max(mx,h[zz]);
            }
            ans+=mx+1;
        }
    }
    cout << ans;
}
int main()
{
    fastio
    //freopen(TASKNAME".INP","r",stdin);
    //freopen(TASKNAME".OUT","w",stdout);
    solve();
}

• Subtask 1: 15 / 15
• Subtask 2: 6 / 6
• Subtask 3: 6 / 6
• Subtask 4: 15 / 15
• Subtask 5: 28 / 28