Submission #646930

#	Time	Username	Problem	Language	Result	Execution time	Memory
646930		BackNoob	Sjekira (COCI20_sjekira)	C++14	110 / 110	59 ms	14172 KiB

sjekira

#pragma GCC optimize ("Ofast")
#pragma GCC target ("avx2")
#include <bits/stdc++.h>
#define ll long long
#define fi first
#define se second
#define endl '\n'
#define MASK(i) (1LL << (i))
#define ull unsigned long long
#define ld long double
#define pb push_back
#define all(x) (x).begin() , (x).end()
#define BIT(x , i) ((x >> (i)) & 1)
#define TASK "task"
#define sz(s) (int) (s).size()

using namespace std;
const int mxN = 3e5 + 227;
const int inf = 1e9 + 277;
const int mod = 1e9 + 7;
const ll infll = 1e18 + 7;
const int base = 307;
const int LOG = 20;
const int block_sz = 500;

template <typename T1, typename T2> bool minimize(T1 &a, T2 b) {
    if (a > b) {a = b; return true;} return false;
}
template <typename T1, typename T2> bool maximize(T1 &a, T2 b) {
    if (a < b) {a = b; return true;} return false;
}

struct DSU{
    int n;
    vector<int> lab;
    vector<int> mx;
    DSU(){}
    DSU(int _n)
    {
        n = _n;
        lab.resize(n + 7, -1);
        mx.resize(n + 7);
    }

    int root(int u) {return lab[u] < 0 ? u : lab[u] = root(lab[u]);}
    bool union_root(int u, int v)
    {
        u = root(u);
        v = root(v);
        if(u == v) return false;
        if(lab[u] > lab[v]) swap(u, v);
        lab[u] += lab[v];
        lab[v] = u;
        maximize(mx[u], mx[v]);
        return true;
    }
} dsu;

int n;
bool used[mxN];
pair<int, int> ed[mxN];
vector<int> adj[mxN];
int idx[mxN];
int best[mxN];

bool cmp(int a, int b)
{
    return dsu.mx[a] < dsu.mx[b];
}

void solve()
{
    cin >> n;

    dsu = DSU(n);
    for(int i = 1; i <= n; i++) cin >> dsu.mx[i];

    for(int i = 1; i <= n; i++) idx[i] = i;
    sort(idx + 1, idx + 1 + n, cmp);

    for(int i = 1; i <= n; i++) best[idx[i]] = i;

    for(int i = 1; i < n; i++) {
        int u, v;
        cin >> u >> v;
        if(best[u] < best[v]) swap(u, v);
        adj[u].pb(v);
    }


    ll res = 0;
    for(int i = 1; i <= n; i++) {
        int u = idx[i];

        for(int v : adj[u]) {
            res += dsu.mx[dsu.root(u)];
            res += dsu.mx[dsu.root(v)];
            dsu.union_root(u, v);
        }
    }



    cout << res;
}


int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    //freopen("task.inp", "r", stdin);
    //freopen("task.out", "w", stdout);

    int tc = 1;
    //cin >> tc;
    while(tc--) {
        solve();
    }
    return 0;
}

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