Submission #727644

#	Time	Username	Problem	Language	Result	Execution time	Memory
727644		marvinthang	Road Closures (APIO21_roads)	C++17	100 / 100	327 ms	71752 KiB

roads

/*************************************
*    author: marvinthang             *
*    created: 21.04.2023 10:12:13    *
*************************************/

#include "roads.h"
#include <bits/stdc++.h>

using namespace std;

#define                  fi  first
#define                  se  second
#define                left  ___left
#define               right  ___right
#define                TIME  (1.0 * clock() / CLOCKS_PER_SEC)
#define             MASK(i)  (1LL << (i))
#define           BIT(x, i)  ((x) >> (i) & 1)
#define  __builtin_popcount  __builtin_popcountll
#define              ALL(v)  (v).begin(), (v).end()
#define           REP(i, n)  for (int i = 0, _n = (n); i < _n; ++i)
#define          REPD(i, n)  for (int i = (n); i--; )
#define        FOR(i, a, b)  for (int i = (a), _b = (b); i < _b; ++i) 
#define       FORD(i, b, a)  for (int i = (b), _a = (a); --i >= _a; ) 
#define       FORE(i, a, b)  for (int i = (a), _b = (b); i <= _b; ++i) 
#define      FORDE(i, b, a)  for (int i = (b), _a = (a); i >= _a; --i) 
#define        scan_op(...)  istream & operator >> (istream &in, __VA_ARGS__ &u)
#define       print_op(...)  ostream & operator << (ostream &out, const __VA_ARGS__ &u)
#ifdef LOCAL
    #include "debug.h"
#else
    #define file(name) if (fopen(name".inp", "r")) { freopen(name".inp", "r", stdin); freopen(name".out", "w", stdout); }
    #define DB(...) 23
    #define db(...) 23
    #define debug(...) 23
#endif

template <class U, class V> scan_op(pair <U, V>)  { return in >> u.first >> u.second; }
template <class T> scan_op(vector <T>)  { for (size_t i = 0; i < u.size(); ++i) in >> u[i]; return in; }
template <class U, class V> print_op(pair <U, V>)  { return out << '(' << u.first << ", " << u.second << ')'; }
template <size_t i, class T> ostream & print_tuple_utils(ostream &out, const T &tup) { if constexpr(i == tuple_size<T>::value) return out << ")";  else return print_tuple_utils<i + 1, T>(out << (i ? ", " : "(") << get<i>(tup), tup); }
template <class ...U> print_op(tuple<U...>) { return print_tuple_utils<0, tuple<U...>>(out, u); }
template <class Con, class = decltype(begin(declval<Con>()))> typename enable_if <!is_same<Con, string>::value, ostream&>::type operator << (ostream &out, const Con &con) { out << '{'; for (__typeof(con.begin()) it = con.begin(); it != con.end(); ++it) out << (it == con.begin() ? "" : ", ") << *it; return out << '}'; }
template <class A, class B> bool minimize(A &a, B b)  { if (a > b) { a = b; return true; } return false; }
template <class A, class B> bool maximize(A &a, B b)  { if (a < b) { a = b; return true; } return false; }

// index from 0
template <class T = int>
    struct Fenwick {

        T *bit = nullptr;
        int n;

        Fenwick(int _n = 0) {
            resize(_n);
        }

        void reset(void) {
            fill(bit, bit + 1 + n, T(0));
        }

        void resize(int _n) {
            if (bit != nullptr) delete[] bit;
            n = _n;
            bit = new T[n + 1];
            reset();
        }

        void update(int i, T val) {
            assert(0 <= i);
            ++i;
            for (; i <= n; i += i & -i) bit[i] += val;
        }

        T get(int i) {
            if (i < 0) return T(0);
            ++i;
            i = min(i, n);
            T res(0);
            for (; i > 0; i -= i & -i)
                res += bit[i];
            return res;
        }

        int upper_bound(T val) {
            int res = 0;
            for (int i = __lg(n); i >= 0; --i) {
                if ((res | MASK(i)) <= n && val >= bit[res | MASK(i)]) {
                    res |= MASK(i);
                    val -= bit[res];
                }
            }
            return res;
        }

        int lower_bound(T val) {
            int res = 0;
            for (int i = __lg(n); i >= 0; --i) {
                if ((res | MASK(i)) <= n && val > bit[res | MASK(i)]) {
                    res |= MASK(i);
                    val -= bit[res];
                }
            }
            return res;
        }

    };

// end of template

const int MAX = 1e5 + 5;
const long long INF = 1e18;

int N, K, visited[MAX];
long long dp[MAX][2];
set <pair <int, int>, greater <pair <int, int>>> adj[MAX];
vector <int> values[MAX];
Fenwick <int> cnt[MAX];
Fenwick <long long> sum[MAX];
map <int, int> id[MAX];

void dfs(int u) {
    dp[u][0] = INF; dp[u][1] = 0;
    visited[u] = K;
    vector <long long> change;
    for (auto [w, v]: adj[u]) if (visited[v] != K) {
        dfs(v);
        dp[u][1] += dp[v][1] + w;
        if (dp[v][0] < dp[v][1] + w) change.push_back(dp[v][0] - dp[v][1] - w);
    }
    sort(ALL(change));
    if (K) {
        dp[u][1] += sum[u].get(values[u].size());
        long long res = INF;
        REP(i, min((int) change.size(), K) + 1) {
            int need = K - i;
            int p = cnt[u].lower_bound(need);
            long long cur = dp[u][1] - sum[u].get(p);
            long long ma = -INF;
            if (p && p <= values[u].size()) ma = -values[u][p - 1];
            else ma = 0;
            if (i) maximize(ma, change[i - 1]);
            if (i == K) ma = change[i - 1];
            minimize(res, cur);
            minimize(dp[u][0], cur - ma);
            if (i < change.size()) dp[u][1] += change[i];
        }
        dp[u][1] = res;
    }
}

vector <long long> minimum_closure_costs(int n, vector<int> U, vector<int> V, vector<int> W) {
    N = n;
    REP(i, N - 1) {
        adj[U[i]].insert(make_pair(W[i], V[i]));
        adj[V[i]].insert(make_pair(W[i], U[i]));
    }
    vector <pair <int, int>> pos;
    REP(i, N) pos.emplace_back(adj[i].size(), i);
    sort(ALL(pos));
    vector <long long> res(N);
    int ptr = 0;
    memset(visited, -1, N * sizeof(int));
    REP(u, N) {
        int c = 0;
        set <pair <int, int>> nxt;
        for (auto [w, v]: adj[u]) {
            values[u].push_back(w);
            id[u][v] = ++c;
        }
        cnt[u].resize(c + 1);
        sum[u].resize(c + 1);
    }
    REP(k, N) {
        K = k;
        while (ptr < N && pos[ptr].fi <= K) {
            int u = pos[ptr++].se;
            for (auto [w, v]: adj[u]) {
                adj[v].erase(make_pair(w, u));
                int x = id[v][u];
                cnt[v].update(x, +1);
                sum[v].update(x, +w);
            }
        }
        FOR(i, ptr, N) {
            int u = pos[i].se;
            if (visited[u] == K) continue;
            dfs(u);
            res[K] += dp[u][1];
        }
    }
    return res;
}

#ifdef LOCAL
#include "roads.h"

#include <cassert>
#include <cstdio>

#include <vector>

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

  std::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]));
  }

  std::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;
}
#endif

Compilation message (stderr)

roads.cpp: In function 'void dfs(int)':
roads.cpp:139:24: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  139 |             if (p && p <= values[u].size()) ma = -values[u][p - 1];
      |                      ~~^~~~~~~~~~~~~~~~~~~
roads.cpp:145:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  145 |             if (i < change.size()) dp[u][1] += change[i];
      |                 ~~^~~~~~~~~~~~~~~

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