Submission #374303

#	Time	Username	Problem	Language	Result	Execution time	Memory
374303		kartel	Sjekira (COCI20_sjekira)	C++14	110 / 110	94 ms	8928 KiB

sjekira

#include <bits/stdc++.h>
#define in(x) freopen(x, "r", stdin)
#define out(x) freopen(x, "w", stdout)
//#include <time.h>
//#include <ext/pb_ds/assoc_container.hpp>
//#include <ext/pb_ds/tree_policy.hpp>
//#pragma GCC optimize("Ofast")
//#pragma GCC optimize("unroll-loops")
//#pragma GCC optimize("-O3")
#define F first
#define S second
#define pb push_back
//#define M ll(1e9 + 7)
#define M ll(998244353)
#define sz(x) (int)x.size()
#define re return
#define oo ll(1e18)
#define el '\n'
#define pii pair <int, int>
#define all(x) (x).begin(), (x).end()
#define arr_all(x, n) (x + 1), (x + 1 + n)
#define vi vector<int>
#define eps (ld)1e-9
using namespace std;
typedef long long ll;
//using namespace __gnu_pbds;
//typedef tree <ll, null_type, less_equal <ll> , rb_tree_tag, tree_order_statistics_node_update> ordered_set;
typedef double ld;
typedef unsigned long long ull;
typedef short int si;

const int N = 1e5 + 500;

int pr[N], mx[N], siz[N];
int n, cost[N], num[N];
vector <int> g[N];
ll ans;
bool mk[N];

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

void link(int x, int y) {
    x = f(x);
    y = f(y);

    if (siz[x] > siz[y]) {
        swap(x, y);
    }
    mx[y] = max(mx[x], mx[y]);
    pr[x] = y;
    siz[y] += siz[x];
}

bool cmp(int _i, int _j) {return (cost[_i] > cost[_j]);}

int main()
{
//    mt19937 rnd(chrono::steady_clock::now().time_since_epoch().count());;
	ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
//	in("toys.in");
//	out("toys.out");
//    in("input.txt");
//    out("output.txt");
//    cerr.precision(9); cerr << fixed;

//    clock_t tStart = clock();

    cin >> n;
    for (int i = 1; i <= n; i++) {
        cin >> cost[i];
        num[i] = i;
    }

    for (int i = 1; i < n; i++) {
        int u, v;
        cin >> u >> v;

        g[u].pb(v);
        g[v].pb(u);
    }

    sort(arr_all(num, n), cmp);

    vector <pii> vc;

    for (int i = 1; i <= n; i++) {
        int v = num[i];
        for (auto u : g[v]) {
            if (mk[u])
                continue;

            vc.pb({u, v});
        }
        mk[v] = 1;
    }

    reverse(all(vc));

    for (int i = 1; i <= n; i++) {
        pr[i] = i;
        siz[i] = 1;
        mx[i] = cost[i];
    }

    for (auto pi : vc) {
        int v = pi.F;
        int u = pi.S;

        if (f(v) == f(u)) {
            continue;
        }

        if (cost[v] < cost[u]) {
            swap(u, v);
        }

        ans += cost[v];
        ans += mx[f(u)];

        link(v, u);
    }

    cout << ans;
}


/*

7
4 6 7 2 3 1 5
*/

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