Submission #852607

#	Time	Username	Problem	Language	Result	Execution time	Memory
852607		12345678	Stranded Far From Home (BOI22_island)	C++17	100 / 100	94 ms	21152 KiB

island

#include <bits/stdc++.h>

using namespace std;

#define ll long long

const int nx=2e5+5;
ll n, m, sz[2*nx], u, v, dsu[2*nx], cnt;
vector<tuple<int, int, int>> d;
vector<pair<int, int>> p;
bool can[2*nx];

int find(int x)
{
    if (dsu[x]==x) return x;
    return dsu[x]=find(dsu[x]);
}

void dfs(int u)
{
    if (u<=n) return;
    if (!can[u]) can[p[u].first]=can[p[u].second]=0;
    dfs(p[u].first); dfs(p[u].second);
}

int main()
{
    cin.tie(NULL)->sync_with_stdio(false);
    cin>>n>>m;
    for (int i=1; i<=2*n; i++) can[i]=1, dsu[i]=i;
    for (int i=1; i<=n; i++) cin>>sz[i];
    for (int i=0; i<m; i++) cin>>u>>v, d.push_back({max(sz[u], sz[v]), u, v});
    sort(d.begin(), d.end());
    p.resize(n+1); cnt=n;
    for (int i=0; i<m; i++)
    {
        auto [w, u, v]=d[i];
        int pu=find(u), pv=find(v);
        if (pu==pv) continue;
        if (sz[pu]<w) can[pu]=0;
        if (sz[pv]<w) can[pv]=0;
        dsu[pu]=dsu[pv]=++cnt;
        sz[cnt]=sz[pu]+sz[pv];
        p.push_back({pu, pv});
    }
    dfs(cnt);
    for (int i=2; i<=n; i++) 
    {
        if (find(i)!=find(1)) 
        {
            cout<<string(n, '0');
            return 0;
        }
    }
    for (int i=1; i<=n; i++) cout<<(can[i]?'1':'0');
}

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