Submission #1110085

#	Time	Username	Problem	Language	Result	Execution time	Memory
1110085		otarius	Sjekira (COCI20_sjekira)	C++17	110 / 110	146 ms	20668 KiB

sjekira

#include <bits/stdc++.h>
#include <bits/extc++.h>
using namespace __gnu_pbds;
using namespace std;

// #pragma GCC optimize("Ofast")
// #pragma GCC optimize ("unroll-loops")
// #pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")

#define ff first
#define sc second
#define pb push_back
#define ll long long
#define pll pair<ll, ll>
#define pii pair<int, int>
#define ull unsigned long long
#define all(x) (x).begin(),(x).end()
#define rall(x) (x).rbegin(),(x).rend()

// #define int long long
// #define int unsigned long long

// #define ordered_set(T) tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>
// #define ordered_multiset(T) tree<T, null_type, less_equal<T>, rb_tree_tag, tree_order_statistics_node_update>

void open_file(string filename) {
    freopen((filename + ".in").c_str(), "r", stdin);
    freopen((filename + ".out").c_str(), "w", stdout);
}

// const ll mod = 1e9 + 7;
// const ll mod = 998244353;

const ll inf = 1e9;
const ll biginf = 1e18;
const int maxN = 1e5 + 25;

set<pii> ers;
vector<int> g[maxN];
int par[maxN], mx[maxN], t[maxN];
void make_set(int n) {
    for (int i = 1; i <= n; i++) {
        par[i] = i; mx[i] = t[i];
    }
}
int find_set(int v) {
    if (par[v] == v)
        return v;
    return par[v] = find_set(par[v]);
}
int union_set(int x, int y) {
    x = find_set(x);
    y = find_set(y);
    if (x == y) return 0;
    int ans = mx[x] + mx[y];
    par[y] = x; mx[x] = max(mx[x], mx[y]);
    return ans;
}
void solve() {
    int n;
    cin >> n;
    pii d[n + 1];
    for (int i = 1; i <= n; i++) {
        cin >> d[i].ff; d[i].sc = i; t[i] = d[i].ff;
    } sort(d + 1, d + n + 1);
    for (int i = 1; i < n; i++) {
        int x, y; cin >> x >> y;
        g[x].pb(y); g[y].pb(x);
    } ll ans = 0;
    vector<pii> ord;
    for (int i = n; i >= 1; i--) {
        for (int x : g[d[i].sc]) {
            if (ers.find({d[i].sc, x}) == ers.end()) {
                ers.insert({d[i].sc, x});
                ers.insert({x, d[i].sc});
                ord.pb({d[i].sc, x});
            }
        }
    } make_set(n); reverse(all(ord));
    for (auto x : ord) {
        ans += union_set(x.ff, x.sc);
    } cout << ans;
}
int32_t main() { 
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr); cout.tie(nullptr);
    
    int t = 1;
    // cin >> t;
    while (t--) {
        solve();
        cout << '\n';
    }
    return 0;
}

Compilation message (stderr)

sjekira.cpp: In function 'void open_file(std::string)':
sjekira.cpp:27:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   27 |     freopen((filename + ".in").c_str(), "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
sjekira.cpp:28:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   28 |     freopen((filename + ".out").c_str(), "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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