Submission #598041

#	Time	Username	Problem	Language	Result	Execution time	Memory
598041		boris_mihov	Stranded Far From Home (BOI22_island)	C++14	100 / 100	215 ms	31068 KiB

island

#include <algorithm>
#include <iostream>
#include <numeric>
#include <cassert>
#include <vector>

typedef long long llong;
const int MAXN = 200000 + 10;
const int INF = 1e9 + 10;

int n, m;
int a[MAXN], s[MAXN], inS[MAXN];
std::vector < int > g[MAXN];
std::vector < int > alive[MAXN];
struct DSUelement
{
    int par;
    int sum;
} c[MAXN];

int find(int x)
{
    if (c[x].par == x) return x;
    return c[x].par = find(c[x].par);
}

void connect(int x, int y)
{
    x = find(x);
    y = find(y);
    if (alive[x].size() > alive[y].size()) std::swap(x, y);
    c[x].par = y;
    c[y].sum += c[x].sum;
    c[y].sum = std::min(c[y].sum, INF);
    alive[y].reserve(alive[x].size());
    for (int i : alive[x])
    {
        alive[y].push_back(i);
    }
}

bool areConnected(int x, int y)
{
    return find(x) == find(y);
}

char ans[MAXN];
void solve()
{
    std::iota(s+1, s+n+1, 1);
    std::sort(s+1, s+n+1, [&](int x, int y)
    {
        return a[x] < a[y];
    });

    for (int i = 1 ; i <= n ; ++i)
    {
        inS[s[i]] = i;
        c[i].par = i;
        c[i].sum = a[i];
        alive[i].push_back(i);
    }

    for (int i = 1 ; i <= n ; ++i)
    {
        int x = s[i];
        for (const int &j : g[x])
        {
            if (inS[j] > i || areConnected(x, j)) continue;
            int par = find(j);
            if (c[par].sum < a[x])
            {
                alive[par].clear();
            }

            connect(x, j);
        }
    }

    int findPar = find(1);
    std::fill(ans, ans+n, '0');
    for (int i : alive[findPar])
    {
        ans[i-1] = '1';
    }

    ans[n] = '\0';
    std::cout << ans << '\n';
}

void read()
{
    std::cin >> n >> m;
    for (int i = 1 ; i <= n ; ++i)
    {
        std::cin >> a[i];
    }

    for (int i = 1 ; i <= m ; ++i)
    {
        int x, y;
        std::cin >> x >> y;
        g[x].push_back(y);
        g[y].push_back(x);
    }
}

void fastIO()
{
    std::ios_base :: sync_with_stdio(0);
    std::cout.tie(nullptr);
    std::cin.tie(nullptr);
}

int main()
{
    fastIO();
    read();
    solve();

    return 0;
}

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