Submission #1243649

#	Time	Username	Problem	Language	Result	Execution time	Memory
1243649		chikien2009	Stranded Far From Home (BOI22_island)	C++20	100 / 100	145 ms	37512 KiB

island

#include <bits/stdc++.h>

using namespace std;

void setup()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
}

struct DSU
{
    int par[200000], sz[200000];
    long long val[200000];
    vector<int> v[200000];
    inline DSU()
    {
        for (int i = 0; i < 2e5; ++i)
        {
            par[i] = i;
            sz[i] = 1;
            val[i] = 0;
        }
    }
    inline int Get(int inp)
    {
        return (inp == par[inp] ? inp : par[inp] = Get(par[inp]));
    }
    inline bool Combine(int ina, int inb)
    {
        ina = Get(ina);
        inb = Get(inb);
        if (ina == inb)
        {
            return 0;
        }
        if (sz[ina] < sz[inb])
        {
            swap(ina, inb);
        }
        par[inb] = ina;
        sz[ina] += sz[inb];
        val[ina] += val[inb];
        for (auto &i : v[inb])
        {
            v[ina].push_back(i);
        }
        v[inb].clear();
        return 1;
    }
} dsu;

int n, m, a, b;
vector<int> g[200000];
pair<int, int> s[200000];
bool check[200000];
set<int> adj;

int main()
{
    setup();

    cin >> n >> m;
    for (int i = 0; i < n; ++i)
    {
        cin >> s[i].first;
        s[i].second = i;
    }
    while (m--)
    {
        cin >> a >> b;
        g[a - 1].push_back(b - 1);
        g[b - 1].push_back(a - 1);
    }
    sort(s, s + n);
    for (int i = 0; i < n; ++i)
    {
        adj.clear();
        a = s[i].second;
        b = s[i].first;
        dsu.val[a] = b;
        dsu.v[a] = {a};
        check[s[i].second] = true;
        for (auto &j : g[a])
        {
            if (check[j])
            {
                adj.insert(dsu.Get(j));
            }
        }
        for (auto &j : adj)
        {
            if (dsu.val[j] < b)
            {
                dsu.v[j].clear();
            }
            dsu.Combine(j, a);
        }
    }
    a = dsu.Get(0);
    fill_n(check, 2e5, 0);
    for (auto & i : dsu.v[a])
    {
        check[i] = true;
    }
    for (int i = 0; i < n; ++i)
    {
        cout << check[i];
    }
    return 0;
}

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