Submission #1079941

#	Time	Username	Problem	Language	Result	Execution time	Memory
1079941		LIF	Stranded Far From Home (BOI22_island)	C++14	100 / 100	363 ms	77760 KiB

island

#include<bits/stdc++.h>
using namespace std;
int n,m,cnt = 0;
long long int a[500005],head[500005];
int x[500005];
int y[500005];
vector<long long int> val;
map<int,vector<int> > mp;
int f[500005];
vector<int> vv[500005];
long long int siz[500005];
int tag[500005];
int find(int x)
{
    if(f[x] == x)return x;
    return f[x] = find(f[x]);
}
struct e
{
    int to;
    int next;
}edge[500005];
void add(int x,int y)
{
    cnt++;
    edge[cnt].to = y;
    edge[cnt].next = head[x];
    head[x] = cnt;
}
void dfs(int now,int fa,int tg)
{
    tag[now] = tg;
    for(int i=head[now];i!=0;i=edge[i].next)
    {
        int to = edge[i].to;
        if(to == fa)continue;
        if(tag[to] == -1 || tg == -1)dfs(to,now,-1);
        else dfs(to,now,1);
    }
}
int main()
{
    cin>>n>>m;
    for(int i=1;i<=n;i++)
    {
        cin>>a[i];
        if(mp[a[i]].size() == 0)val.push_back(a[i]);
        mp[a[i]].push_back(i);
        tag[i] = 1;
    }
    for(int i=1;i<=n;i++)siz[i] = a[i];
    for(int i=1;i<=n;i++)f[i] = i;
    for(int i=1;i<=m;i++)
    {
        cin>>x[i]>>y[i];
        vv[x[i]].push_back(y[i]);vv[y[i]].push_back(x[i]);
    }
    sort(val.begin(),val.end());
    for(int i=0;i<val.size();i++)
    {
        for(auto nowid : mp[val[i]])
        {
            for(auto toid : vv[nowid])
            {
                if(a[toid] <= a[nowid])
                {
                    if(find(toid) == find(nowid))continue;

                        if(val[i] > siz[find(toid)])
                        {
                            tag[find(toid)] = -1;
                            //cout<<"fail"<<endl;
                            //cout<<val[i]<<" "<<toid<<" "<<siz[toid]<<endl;
                        }
                        siz[find(nowid)] += siz[find(toid)];
                        add(find(nowid),find(toid));
                        f[find(toid)] = find(nowid);
                        //cout<<"yeah"<<endl;
                        //cout<<find(nowid)<<" "<<find(toid)<<endl;
                        //cout<<"set: "<<endl;
                        //for(int j=1;j<=n;j++)cout<<find(j)<<" "<<siz[find(j)]<<endl;
                        //cout<<endl;
                }
            }
            
        }
    }
    // for(int i=1;i<=n;i++)cout<<tag[i];
    // cout<<endl;

    int fir = find(1);
    dfs(fir,0,1);
    for(int i=1;i<=n;i++)
    {
        if(tag[i] == -1)cout<<"0";
        else cout<<"1";
    }
    cout<<endl;

    









    return 0;
}

Compilation message (stderr)

island.cpp: In function 'int main()':
island.cpp:59:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   59 |     for(int i=0;i<val.size();i++)
      |                 ~^~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 10 / 10
• Subtask 3: 15 / 15
• Subtask 4: 30 / 30
• Subtask 5: 35 / 35