Submission #821379

#	Time	Username	Problem	Language	Result	Execution time	Memory
821379		Denkata	Marshmallow Molecules (CCO19_day2problem2)	C++14	10 / 25	758 ms	1048576 KiB

Main

#include<bits/stdc++.h>
using namespace std;
const int maxn = 2e5+3;
int i,j,p,q,n,m,k;
long long ans;
set <int> s[maxn];
set <int> Merge(set <int> a,set <int> b)
{
    if(b.empty())
        return a;
    if(a.empty())
        return b;
    if(a.size()<b.size())
        swap(a,b);
    a.insert(b.begin(),b.end());
    return a;
}
int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
    cin>>n>>m;
    for(i=1;i<=m;i++)
    {
        cin>>p>>q;
        s[p].insert(q);
    }
    for(i=1;i<=n;i++)
    {
        if(s[i].size()==0)continue;
        ans+=(long long)s[i].size();
        p = *s[i].begin();s[i].erase(p);
        if(s[i].size()==0 && s[p].size()==0)continue;
        s[p] = Merge(s[i],s[p]);
    }
    cout<<ans<<endl;
    return 0;
}

• Subtask 1: 5 / 5
• Subtask 2: 5 / 5
• Subtask 3: 0 / 5
• Subtask 4: 0 / 10