Submission #574509

#	Time	Username	Problem	Language	Result	Execution time	Memory
574509		stevancv	Stranded Far From Home (BOI22_island)	C++14	100 / 100	219 ms	25716 KiB

island

#include <bits/stdc++.h>
#define ll long long
#define ld long double
#define sp ' '
#define en '\n'
#define smin(a, b) a = min(a, b)
#define smax(a, b) a = max(a, b)
using namespace std;
const int N = 2e5 + 2;
int mod = 1000000007;
int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    int n, m;
    cin >> n >> m;
    vector<ll> s(n), sum(n);
    for (int i = 0; i < n; i++) {
        cin >> s[i];
        sum[i] = s[i];
    }
    vector<int> a(m), b(m);
    for (int i = 0; i < m; i++) {
        cin >> a[i] >> b[i];
        a[i] -= 1;
        b[i] -= 1;
        if (s[a[i]] > s[b[i]]) swap(a[i], b[i]);
    }
    vector<int> order(m);
    iota(order.begin(), order.end(), 0);
    sort(order.begin(), order.end(), [&] (int i, int j) {
        return s[b[i]] < s[b[j]];
    });
    vector<int> p(n);
    iota(p.begin(), p.end(), 0);
    function<int(int)> Find = [&] (int x) {
        if (x == p[x]) return x;
        return p[x] = Find(p[x]);
    };
    vector<vector<int>> g(n);
    function<void(int, int)> Unite = [&] (int u, int v) {
        u = Find(u);
        v = Find(v);
        p[u] = v;
        sum[v] += sum[u];
        g[u].push_back(v);
    };
    vector<bool> can(n, 1);
    for (int i : order) {
        int x = Find(a[i]);
        int y = Find(b[i]);
        if (x == y) continue;
        if (sum[x] < s[y]) can[x] = 0;
        Unite(x, y);
    }
    vector<bool> was(n);
    function<int(int)> Dfs = [&] (int s) {
        if (was[s]) return can[s];
        was[s] = 1;
        for (int u : g[s]) {
            if (Dfs(u) == 0) can[s] = 0;
        }
        return can[s];
    };
    for (int i = 0; i < n; i++) {
        if (!was[i]) Dfs(i);
    }
    for (int i = 0; i < n; i++) cout << can[i];
    cout << en;
    return 0;
}

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