Submission #984470

#	Time	Username	Problem	Language	Result	Execution time	Memory
984470		Marcus	Road Closures (APIO21_roads)	C++17	0 / 100	40 ms	7880 KiB

roads

#include "roads.h"
#include <vector>
#include <bits/stdc++.h>
using namespace std;
#define ll long long

const ll N1 = 1e5;
vector<int> chain(N1);
vector<int> portion(N1, 1);

int find(int x) {
    while (x != chain[x]) x = chain[x];
    return x;
}

bool same(int a, int b) {
    return find(a) == find(b);
}

void unite(int a, int b) {
    a = find(a);
    b = find(b);
    if (portion[a] < portion[b]) swap(a,b);
    portion[a] += portion[b];
    chain[b] = a;
}

std::vector<long long> minimum_closure_costs(int N, std::vector<int> U,
                                             std::vector<int> V,
                                             std::vector<int> W) {
  
    vector<tuple<ll, ll, ll>> edge(N-1);
    for (int i=0; i<N-1; i++)
    {
        edge[i] = {W[i], U[i], V[i]};
    }
    sort(edge.begin(), edge.end());
    reverse(edge.begin(), edge.end());

    for (int i=0; i<N; i++) {chain[i] = i;}

    ll reduction = 0;
    ll total = 0;
    for (auto e: edge)
    {
        ll c = get<0>(e); ll u = get<1>(e); ll v = get<2>(e);
        total += c;
        if (portion[find(u)] == 1 && portion[find(v)] == 1) {unite(u, v); reduction += c;}
    }
    //cout<<"\n";

    vector<ll> answer = {total, total - reduction};
    for (int i=0; i<N-2; i++) {answer.push_back(0);}

    return answer;
}

• Subtask 1: 0 / 5
• Subtask 2: 0 / 7
• Subtask 3: 0 / 14
• Subtask 4: 0 / 10
• Subtask 5: 0 / 17
• Subtask 6: 0 / 25
• Subtask 7: 0 / 22