Submission #374302

#	Time	Username	Problem	Language	Result	Execution time	Memory
374302		NONAME	Sjekira (COCI20_sjekira)	C++17	110 / 110	85 ms	11236 KiB

sjekira

#include <bits/stdc++.h>
using namespace std;
mt19937 rnd(chrono::steady_clock::now().time_since_epoch().count());

const int man = (int)(1e5 + 500);

int n;
int sz[man], c[man], pr[man], x[man], y[man];
long long a[man], val[man];
bool was[man];
vector <array <int, 2> > g[man];
vector <array <int, 2> > ops;

int f(int x) {
    return (x == pr[x]) ? x : pr[x] = f(pr[x]);
}

void un(int x, int y) {
    x = f(x);
    y = f(y);
    if (sz[x] < sz[y]) {
        swap(x, y);
    }
    
    val[x] = max(val[x], val[y]);
    sz[x] += sz[y];
    pr[y] = x;
}

bool cmp(int x, int y) {
    return (a[x] > a[y]);
}

int main() {
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);

    cin >> n;

    for (int i = 0; i < n; ++i) {
        cin >> a[i];
        c[i] = i;
        pr[i] = i;
        val[i] = a[i];
        sz[i] = 1;
    }

    for (int i = 0; i < (n - 1); ++i) {
        cin >> x[i] >> y[i];
        --x[i], --y[i];

        g[x[i]].push_back({y[i], i});
        g[y[i]].push_back({x[i], i});
    }

    sort(c, c + n, cmp);

    for (int i = 0; i < n; ++i) {
        int v = c[i];
        for (auto& u : g[v]) {
            if (was[u[1]] == true) {
                continue;
            }
            was[u[1]] = true;
            ops.push_back({v, u[0]});
        }
    }

    long long ans = 0;
    reverse(ops.begin(), ops.end());
    // cerr << (int)(ops.size()) << "\n";
    for (auto& i : ops) {
        ans += val[f(i[0])] + val[f(i[1])];
        un(i[0], i[1]);
    }

    cout << ans << "\n";

    return 0;
}

• Subtask 1: 10 / 10
• Subtask 2: 10 / 10
• Subtask 3: 30 / 30
• Subtask 4: 60 / 60