Submission #1114857

#	Time	Username	Problem	Language	Result	Execution time	Memory
1114857		vladilius	Road Closures (APIO21_roads)	C++17	31 / 100	2079 ms	66240 KiB

roads

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using pii = pair<int, int>;
using pil = pair<int, ll>;
using pll = pair<ll, ll>;
#define pb push_back
#define ff first
#define ss second
#define arr3 array<ll, 3>
 
struct DS{
    multiset<ll> st;
    void add(ll x){
        st.insert(x);
    }
    void rem(ll x){
        st.erase(st.find(x));
    }
    int sz(){
        return (int) st.size();
    }
    ll get(int k){
      	if (st.empty()) return 0;
        k = min(k, sz());
        ll out = 0;
        auto it = prev(st.end());
        for (int i = 0; i < k; i++){
            out += (*it);
            if (i == (k - 1)) break;
            it--;
        }
        return out;
    }
};
 
vector<ll> minimum_closure_costs(int n, vector<int> U, vector<int> V, vector<int> W){
    vector<pii> g[n + 1];
    ll tot = 0;
    for (int i = 0; i < n - 1; i++){
        int u = U[i] + 1, v = V[i] + 1, w = W[i];
        g[u].pb({v, w});
        g[v].pb({u, w});
        tot += w;
    }
    
    vector<pil> ch1[n + 1], ch2[n + 1];
    vector<pll> p(n + 1);
    vector<ll> W1(n + 1);
    function<void(int, int)> dfs = [&](int v, int pr){
        if ((g[v].size() + !pr) == 1){
            ch1[v] = {{0, 0}};
            ch2[v] = {{0, 0}};
            return;
        }
        for (auto [i, w]: g[v]){
            if (i == pr) continue;
            dfs(i, v);
        }
        
        vector<arr3> t;
        DS T;
        for (auto [i, w]: g[v]){
            if (i == pr) continue;
            p[i].ff = p[i].ss = 0;
            T.add(w);
            W1[i] = w;
            for (auto [j, x]: ch1[i]){
                t.pb({j, i, x});
            }
            for (auto [j, x]: ch2[i]){
                t.pb({j, -i, x});
            }
        }
        
        sort(t.begin(), t.end());
        int p1 = 0; ll sum = 0;
        while (p1 < t.size()){
            int p2 = p1;
            while (p2 < t.size() && t[p1][0] == t[p2][0]){
                auto [j, i, x] = t[p2];
                if (i > 0){
                    ll f = p[i].ff + W1[i] - p[i].ss;
                    if (f > 0) T.rem(f);
                    p[i].ff = x;
                    f = p[i].ff + W1[i] - p[i].ss;
                    if (f > 0) T.add(f);
                }
                else {
                    i = -i;
                    sum -= p[i].ss;
                    ll f = p[i].ff + W1[i] - p[i].ss;
                    if (f > 0) T.rem(f);
                    p[i].ss = x;
                    f = p[i].ff + W1[i] - p[i].ss;
                    if (f > 0) T.add(f);
                    sum += p[i].ss;
                }
                p2++;
            }
            
            ch2[v].pb({t[p1][0], sum + T.get((int) t[p1][0])});
            if (!t[p1][0]) ch1[v].pb({0, sum});
            else ch1[v].pb({t[p1][0], sum + T.get((int) t[p1][0] - 1)});
 
            int R = (int)((p2 == (int) t.size()) ? n : t[p2][0]);
            for (int j = (int) t[p1][0] + 1; j <= min(R - 1, T.sz()); j++){
                ch2[v].pb({j, sum + T.get(j)});
            }
            for (int j = (int) t[p1][0] + 1; j <= min(R - 1, T.sz() + 1); j++){
                if (!j) ch1[v].pb({0, sum});
                else ch1[v].pb({j, sum + T.get(j - 1)});
            }
            p1 = p2;
        }
    };
    dfs(1, 0);
    
    vector<ll> dp(n);
    for (int i = 0; i < ch2[1].size(); i++){
        int R = (i == (ch2[1].size() - 1)) ? n : ch2[1][i + 1].ff;
        for (int j = ch2[1][i].ff; j < R; j++){
            dp[j] = ch2[1][i].ss;
        }
    }
    
    vector<ll> out;
    for (int i = 0; i < n; i++){
        out.pb(tot - dp[i]);
    }
    return out;
}

Compilation message (stderr)

roads.cpp: In lambda function:
roads.cpp:78:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::array<long long int, 3> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   78 |         while (p1 < t.size()){
      |                ~~~^~~~~~~~~~
roads.cpp:80:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::array<long long int, 3> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   80 |             while (p2 < t.size() && t[p1][0] == t[p2][0]){
      |                    ~~~^~~~~~~~~~
roads.cpp: In function 'std::vector<long long int> minimum_closure_costs(int, std::vector<int>, std::vector<int>, std::vector<int>)':
roads.cpp:120:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  120 |     for (int i = 0; i < ch2[1].size(); i++){
      |                     ~~^~~~~~~~~~~~~~~
roads.cpp:121:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  121 |         int R = (i == (ch2[1].size() - 1)) ? n : ch2[1][i + 1].ff;
      |                  ~~^~~~~~~~~~~~~~~~~~~~~~

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