Submission #1244827

#	Time	Username	Problem	Language	Result	Execution time	Memory
1244827		CrabCNH	Sjekira (COCI20_sjekira)	C++20	110 / 110	44 ms	11076 KiB

sjekira

#include <bits/stdc++.h>

#define int long long
#define pii pair<int, int>
#define fi first
#define se second

using namespace std;

const int N = 1e5 + 5;

int a[N];

void read() {
    #define task "KB"
    if (fopen(task".inp", "r")) {
        freopen(task".inp", "r", stdin);
        freopen(task".out", "w", stdout);
    }
}

struct edge {
    int u, v, c;
};

struct node {
    int id, val;
};

bool cmpnode (node A, node B) {
    return A.val < B.val;
}

bool cmpedge(edge a, edge b) {
    return a.c > b.c;
}

int n;
int sz[N + 5], par[N + 5];
int tt[N];
vector<edge> edges;
vector <int> adj[N];
int mx[N + 5];
node t[N];

void init(int n) {
    for (int i = 1; i <= n; i++) {
        par[i] = -1;
        sz[i] = 1;
        mx[i] = t[i].val;
    }
}

int getroot(int u) {
    if (par[u] < 0) {
        return u;
    }
    return par[u] = getroot(par[u]);
}

bool check(int u, int v) {
    return getroot(u) == getroot(v);
}

bool join(int u, int v) {
    u = getroot(u);
    v = getroot(v);
    if (u == v) {
        return 0;
    }
    if (sz[u] < sz[v]) {
        swap(u, v);
    }
    sz[u] += sz[v];
    par[v] = u;
    mx[u] = max (mx[v], mx[u]);
    mx[v] = max (mx[v], mx[u]);
    return 1;
}

signed main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cin >> n;
    for (int i = 1; i <= n; i ++) {
        cin >> t[i].val;;
        t[i].id = i;
        tt[i] = t[i].val;
    }
    init(n);
    for (int i = 1; i <= n - 1; i++) {
        int u, v;
        cin >> u >> v;
        adj[u].push_back (v);
        adj[v].push_back (u);
    }
    int ans = 0;
    sort (t + 1, t + n + 1, cmpnode);
    for (int i = 1; i <= n; i ++) {
        int cur_node = t[i].id;
        int cur_val = t[i].val;
        for (auto v : adj[cur_node]) {
            if (check (cur_node, v) == 1 || mx[getroot (v)] > mx[getroot (cur_node)]) {
                continue;
            }
            else {
                ans += mx[getroot (cur_node)] + mx[getroot (v)];
                join (cur_node, v);
            }
        }
    }
    cout << ans;
    return 0;
}

Compilation message (stderr)

sjekira.cpp: In function 'void read()':
sjekira.cpp:17:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   17 |         freopen(task".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
sjekira.cpp:18:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   18 |         freopen(task".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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