Submission #533577

#	Time	Username	Problem	Language	Result	Execution time	Memory
533577		kartel	Parkovi (COCI22_parkovi)	C++14	10 / 110	529 ms	47924 KiB

Main

#include <bits/stdc++.h>
#define pb push_back
#define F first
#define S second
#define sz(x) (int)x.size()
#define el "\n"
using namespace std;
typedef long long ll;

const int N = 2e5 + 500;

vector <pair <int, int> > g[N];
ll dp[N], cur, best, d[N];
vector <int> ans;
set <pair <ll, int> > se;
bool mk[N];
int n, k;

void dfs(int v, int pr) {
    dp[v] = 0;
    for (auto p : g[v]) {
        int u = p.F, w = p.S;
        if (u == pr || mk[u]) {
            continue;
        }
        dfs(u, v);
        dp[v] = max(dp[u] + w, dp[v]);
    }
}

void go(int v, int pr, ll longest) {
    multiset <ll> se;
    for (auto u : g[v]) {
        if (u.F == pr || mk[u.F]) {
            continue;
        }
        se.insert(dp[u.F] + u.S);
    }

    if (max(longest, dp[v]) < cur) {
        cur = max(longest, dp[v]);
        best = v;
    }
    for (auto u : g[v]) {
        if (u.F == pr || mk[u.F]) {
            continue;
        }
        se.erase(se.find(dp[u.F] + u.S));
        ll nlongest = longest;
        if (sz(se)) {
            nlongest = max(nlongest, *se.rbegin());
        }
        go(u.F, v, nlongest + u.S);
        se.insert(dp[u.F] + u.S);
    }
}

void add(int root, ll w) {
    cur = 1e18;
    dfs(root, -1);
    go(root, -1, w);
    se.insert({cur, best});
}

ll calc() {
    for (int i = 1; i <= n; i++) {
        d[i] = 1e18;
    }
    set <pair <ll, int> > se;
    for (auto x : ans) {
        d[x] = 0;
        se.insert({0, x});
    }
    while (sz(se)) {
        int v = se.begin() -> S;
        se.erase(se.begin());
        for (auto to : g[v]) {
            int u = to.F, w = to.S;
            if (d[u] > d[v] + w) {
                d[u] = d[v] + w;
                se.insert({d[u], u});
            }
        }
    }
    ll ret = 0;
    for (int i = 1; i <= n; i++) {
        ret = max(ret, d[i]);
    }
    return ret;
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(NULL);

    cin >> n >> k;
    for (int i = 1; i < n; i++) {
        int u, v, w;
        cin >> u >> v >> w;
        g[v].pb({u, w});
        g[u].pb({v, w});
    }

    add(1, 0);
    while (k > 0 && sz(se)) {
        k--;
        int del = se.rbegin() -> S;
        se.erase(--se.end());
        mk[del] = 1;
        ans.pb(del);
        for (auto to : g[del]) {
            int u = to.F;
            if (!mk[u]) {
                add(u, to.S);
            }
        }
    }
    cout << calc() << el;
    for (auto x : ans) {
        cout << x << " ";
    }
}

• Subtask 1: 0 / 10
• Subtask 2: 10 / 10
• Subtask 3: 0 / 30
• Subtask 4: 0 / 60