Submission #374298

#TimeUsernameProblemLanguageResultExecution timeMemory
374298ne4eHbKaSjekira (COCI20_sjekira)C++17
110 / 110
82 ms10604 KiB
#include <bits/stdc++.h>
using namespace std;
#ifndef _LOCAL
//#pragma GCC optimize("O3,Ofast")
#else
#pragma GCC optimize("O0")
#endif
template<typename t> inline void umin(t &a, const t b) {a = min(a, b);}
template<typename t> inline void umax(t &a, const t b) {a = max(a, b);}
typedef pair<int, int> pii;
typedef long long ll;
typedef long double ld;
typedef int8_t byte;
ll time() {return chrono::system_clock().now().time_since_epoch().count();}
mt19937 rnd(time());
#define ft first
#define sd second
#define len(f) int((f).size())
#define bnd(f) (f).begin(), (f).end()
#define _ <<' '<<
const int inf = 1e9 + 5;
const ll inf64 = 4e18 + 5;
const int md = 998244353;
namespace MD {
    void add(int &a, const int b) {if((a += b) >= md) a -= md;}
    void sub(int &a, const int b) {if((a -= b) < 0) a += md;}
    int prod(const int a, const int b) {return ll(a) * b % md;}
};

int n;
const int N = 1e5 + 5;
vector<int> g[N];
int t[N];
ll ans;
int p[N], f[N];
int get(int i) {return p[i] == i ? i : p[i] = get(p[i]);}
void unite(int i, int j) {p[i = get(i)] = j = get(j); umax(t[j], t[i]);}

void solve() {
    cin >> n;
    iota(p, p + n, 0);
    for(int i = 0; i < n; ++i) g[i].clear();
    iota(f, f + n, 0);
    for(int i = 0; i < n; ++i) cin >> t[i];
    for(int i = 1; i < n; ++i) {
        int x, y;
        cin >> x >> y;
        --x, --y;
        g[x].push_back(y);
        g[y].push_back(x);
    }
    sort(f, f + n, [&] (const int &a, const int &b) {return t[a] < t[b];});
    ans = 0;
    for(int i = 0; i < n; ++i) {
        int v = f[i];
        for(int u : g[v]) {
            if(t[u] > t[v]) continue;
            if(get(u) != get(v)) {
                ans += t[get(u)] + t[get(v)];
                unite(u, v);
            }
        }
    }
    cout << ans << endl;
}

signed main() {
    ios::sync_with_stdio(false); cin.tie(0); cout.tie(0);
#ifndef _LOCAL
//    freopen("file.in", "r", stdin);
//    freopen("file.out", "w", stdout);
#else
    system("color a");
    freopen("in.txt", "r", stdin);
    int t; cin >> t;
    while(t--)
#endif
    solve();
}
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