Submission #727608

#	Time	Username	Problem	Language	Result	Execution time	Memory
727608		Ozy	Fireworks (APIO16_fireworks)	C++17	100 / 100	313 ms	80356 KiB

fireworks

#include <iostream>
#include <bits/stdc++.h>
using namespace std;
#define rep(i,a,b) for(int i = (a); i <= (b); i++)
#define repa(i,a,b) for(int i = (a); i >= (b); i--)
#define debug(a) cout << #a << " = " << a << endl
#define debugsl(a) cout << #a << " = " << a << ", "
#define lli long long int
#define pll pair<lli,lli>

#define MAX 300000
//para los hijos
#define des first
#define w second

struct x {
    multiset<lli> s;
    lli pend;
    lli ord;
};

lli n,m,a,b,res;
vector<pll> hijos[MAX+2];
lli si[MAX+2];
multiset<lli>::iterator it;

x solve(lli pos,lli dis) {

    x slope;
    slope.s.clear();

    if (pos > n) {   // es un explosivo
        slope.s.insert(dis);
        slope.s.insert(dis);
        slope.pend = 1;
        slope.ord = -dis;
        return slope;
    }

    slope.pend = 0;
    slope.ord = 0;

    for (auto h : hijos[pos]) {
        if (si[h.des] == 0) continue;

        x act = solve(h.des, h.w);
        // aqui mergeo
        if (act.s.size() > slope.s.size()) {
            swap(act.s, slope.s);
            swap(act.pend, slope.pend);
            swap(act.ord, slope.ord);
        }

        for (auto k : act.s) slope.s.insert(k);
        slope.pend += act.pend;
        slope.ord += act.ord;
    }
    while (slope.pend > 1) {
        it = slope.s.end();
        it--;
        slope.ord += (*it);
        slope.s.erase(it);
        slope.pend--;
    }

    // aqui hago la magia del slope
    slope.ord -= dis;
    it = slope.s.end();
    it--;
    lli a = (*it) + dis;
    slope.s.erase(it);
    it = slope.s.end();
    it--;
    lli b = (*it) + dis;
    slope.s.erase(it);

    slope.s.insert(a);
    slope.s.insert(b);

    return slope;
}

void chequeo(lli pos) {

    if (pos > n) {si[pos] = 1; return;}
    for (auto h : hijos[pos]) {
        chequeo(h.des);
        si[pos] = (si[pos]|si[h.des]);
    }
}

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

    cin >> n >> m;
    rep(i,2,n) {
        cin >> a >> b;
        hijos[a].push_back({i,b});
    }
    res = 0;
    rep(i,n+1,n+m) {
        cin >> a >> b;
        if (a > n) res += b;
        else hijos[a].push_back({i,b});
    }
    //eliminar aristas que no tengan ningún explosivo debajo
    chequeo(1);

    x fin = solve(1,0);

    it = fin.s.end();
    it--;
    fin.ord += (*it);
    res += fin.ord;

    cout << res;
}

• Subtask 1: 7 / 7
• Subtask 2: 19 / 19
• Subtask 3: 29 / 29
• Subtask 4: 45 / 45