Submission #1104583

#	Time	Username	Problem	Language	Result	Execution time	Memory
1104583		simona1230	Stranded Far From Home (BOI22_island)	C++17	100 / 100	237 ms	23960 KiB

island

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

int n,m;
int b[200001];
pair<int,int> a[200001];
vector<int> v[200001];
void read()
{
    cin>>n>>m;
    for(int i=1;i<=n;i++)
    {
        cin>>a[i].first;
        b[i]=a[i].first;
        a[i].second=i;
    }
        
    for(int i=1;i<=m;i++)
    {
        int x,y;
        cin>>x>>y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
}

pair<int,int> p[200001];
long long sz[200001];

pair<int,int> parent(int x)
{
    if(x==p[x].first)return p[x];
    pair<int,int> y=parent(p[x].first);
    y.second=max(y.second,p[x].second);
    return p[x]=y;
}

void unite(int i,int j)
{
    pair<int,int> pi=parent(i);
    pair<int,int> pj=parent(j);
    if(pi.first==pj.first)return;
    //cout<<i<<" "<<j<<" "<<pi.first<<" "<<pj.first<<endl;
    
    i=pi.first;
    j=pj.first;
    
    sz[i]+=sz[j];
    p[j].first=i;
}

void solve()
{
    for(int i=1;i<=n;i++)
    {
        p[i].first=i;
        sz[i]=a[i].first;
    }
    sort(a+1,a+n+1);
    for(int i=1;i<=n;i++)
    {
        int vr=a[i].second;
        //cout<<a[i].first<<" "<<vr<<"!"<<endl;
        for(int j=0;j<v[vr].size();j++)
        {
            int nb=v[vr][j];
            pair<int,int> pnb=parent(nb);
            nb=pnb.first;
            if(sz[nb]<sz[vr])
                p[nb].second=1;
        }
        
        for(int j=0;j<v[vr].size();j++)
        {
            int nb=v[vr][j];
            if(b[nb]<=b[vr])
                unite(vr,nb);
        }
    }
    
    for(int i=1;i<=n;i++)
    {
        pair<int,int> p=parent(i);
        cout<<(1^p.second);
    }
    cout<<endl;
}

int main() 
{
    read();
    solve();
    return 0;
}

/*
7 6
2 2 1 1 8 5 5 
1 2
2 3
3 4
4 5
5 6
6 7
*/

Compilation message (stderr)

island.cpp: In function 'void solve()':
island.cpp:65:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   65 |         for(int j=0;j<v[vr].size();j++)
      |                     ~^~~~~~~~~~~~~
island.cpp:74:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   74 |         for(int j=0;j<v[vr].size();j++)
      |                     ~^~~~~~~~~~~~~

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