Submission #501925

#	Time	Username	Problem	Language	Result	Execution time	Memory
501925		Victor	Road Closures (APIO21_roads)	C++17	12 / 100	248 ms	73492 KiB

roads

// #pragma GCC target ("avx,avx2,fma")
// #pragma GCC optimize ("Ofast,inline") // O1 - O2 - O3 - Os - Ofast
// #pragma GCC optimize ("unroll-loops")

#include <bits/stdc++.h>

using namespace std;

#define rep(i, a, b) for (int i = (a); i < (b); ++i)
#define per(i, a, b) for (int i = (b - 1); i >= (a); --i)
#define trav(a, x) for (auto &a : x)

#define all(x) x.begin(), x.end()
#define sz(x) x.size()
#define pb push_back
#define debug(x) cout << #x << " = " << x << endl

#define umap unordered_map
#define uset unordered_set

typedef pair<int, int> ii;
typedef pair<int, ii> iii;
typedef vector<int> vi;
typedef vector<ii> vii;
typedef vector<vi> vvi;

typedef long long ll;
typedef pair<ll, ll> pll;
typedef vector<ll> vll;
typedef vector<pll> vpll;

const int INF = 1'000'000'007;

ll n, k, vis[250001], deg[250001];
set<pll> graph[250001];
ll memo[250001][2], sums[250001];
vpll degree;
multiset<ll> pqs[250001];

void dp(ll u, ll p) {
    vis[u] = k;
    ll ans = sums[u];
    vll diff;

    trav(edge, graph[u]) if (edge.first != p) {
        ll v, w;
        tie(v, w) = edge;
        dp(v, u);
        ans += memo[v][0];
        diff.emplace_back((memo[v][1] + w) - memo[v][0]);
    }

    sort(all(diff));
    diff.emplace_back(1e17);
    memo[u][0] = memo[u][1] = 1e14;
    ll need_rem = max(0LL, deg[u] - k - (ll)sz(pqs[u]));
    vll removed, added;

    rep(i, 0, min(ll(sz(diff) - 1), need_rem)) {
        ll val = diff[i];
        added.pb(val);
        pqs[u].insert(val);
        ans += val;
    }

    if (sz(added) < need_rem)
        memo[u][1] = ans;
    else {
        // debug(u);
        rep(i, need_rem, sz(diff)) {
            memo[u][0] = min(memo[u][0], ans);
            memo[u][1] = min(memo[u][1], ans - max(0LL, *(--pqs[u].end())));

            ll val = diff[i];
            if (val < *(--pqs[u].end())) {
                added.pb(val);
                ans += val;
                auto it = (--pqs[u].end());
                removed.pb(*it);
                ans -= *it;
                pqs[u].erase(it);
                pqs[u].insert(val);

            } else if (val < 0)
                ans += val;
            else
                break;
        }
    }

    trav(val, added) pqs[u].erase(val);
    trav(val, removed) pqs[u].insert(val);

    // cout<<"u = "<<u+1<<" need_rem = "<<need_rem<<' '<<memo[u][0]<<' '<<memo[u][1]<<endl;
}

vector<long long> minimum_closure_costs(int N, vector<int> U, vector<int> V, vector<int> W) {
    n = N;
    memset(vis, -1, sizeof(vis));
    memset(deg, 0, sizeof(deg));
    memset(sums, 0, sizeof(sums));
    degree.assign(n, {0, 0});
    vll ans(n, 0);

    rep(i, 0, n - 1) {
        graph[U[i]].emplace(V[i], W[i]);
        graph[V[i]].emplace(U[i], W[i]);

        ++degree[U[i]].first;
        degree[U[i]].second = U[i];
        ++degree[V[i]].first;
        degree[V[i]].second = V[i];

        ++deg[U[i]];
        ++deg[V[i]];
    }

    sort(all(degree));
    ll removed = 0;
    rep(i, 0, n) {
        k = i;
        while (removed < n && degree[removed].first <= k) {
            int u = degree[removed].second;
            trav(edge, graph[u]) {
                ll v, w;
                tie(v, w) = edge;
                graph[v].erase({u, w});
                sums[v] += w;
                pqs[v].insert(w);
            }
            // debug(u+1);
            ++removed;
        }

        rep(j, removed, n) {
            ll u = degree[j].second;
            while (sz(pqs[u]) > deg[u] - k) {
                auto it = (--pqs[u].end());
                sums[u] -= *it;
                pqs[u].erase(it);
            }
        }

        rep(j, removed, n) if (vis[degree[j].second] != k) {
            ll u = degree[j].second;
            dp(u, u);
            ans[k] += memo[u][0];
        }
    }
    return ans;
}

/*
int main() {
    int N;
    assert(1 == scanf("%d", &N));

    vector<int> U(N - 1), V(N - 1), W(N - 1);
    for (int i = 0; i < N - 1; ++i) {
        assert(3 == scanf("%d %d %d", &U[i], &V[i], &W[i]));
        --U[i];
        --V[i];
    }

    vector<long long> closure_costs = minimum_closure_costs(N, U, V, W);
    for (int i = 0; i < static_cast<int>(closure_costs.size()); ++i) {
        if (i > 0) {
            printf(" ");
        }
        printf("%lld", closure_costs[i]);
    }
    printf("\n");
    return 0;
}*/

Compilation message (stderr)

roads.cpp: In function 'void dp(ll, ll)':
roads.cpp:66:19: warning: comparison of integer expressions of different signedness: 'std::vector<long long int>::size_type' {aka 'long unsigned int'} and 'll' {aka 'long long int'} [-Wsign-compare]
   66 |     if (sz(added) < need_rem)
      |                   ^
roads.cpp:9:42: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
    9 | #define rep(i, a, b) for (int i = (a); i < (b); ++i)
      |                                          ^
roads.cpp:70:9: note: in expansion of macro 'rep'
   70 |         rep(i, need_rem, sz(diff)) {
      |         ^~~
roads.cpp: In function 'std::vector<long long int> minimum_closure_costs(int, std::vector<int>, std::vector<int>, std::vector<int>)':
roads.cpp:137:31: warning: comparison of integer expressions of different signedness: 'std::multiset<long long int>::size_type' {aka 'long unsigned int'} and 'll' {aka 'long long int'} [-Wsign-compare]
  137 |             while (sz(pqs[u]) > deg[u] - k) {
      |                               ^

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