Submission #559161

#	Time	Username	Problem	Language	Result	Execution time	Memory
559161		acm	Road Closures (APIO21_roads)	C++14	7 / 100	520 ms	25752 KiB

roads

#include <bits/stdc++.h>
#define FOR(i, l, r) for (int i = (l); i <= (r); ++i)
#define REP(i, l, r) for (int i = (l); i < (r); ++i)
#define FORD(i, r, l) for (int i = (r); i >= (l); --i)
#define REPD(i, r, l) for (int i = (r)-1; i >= (l); --i)
#define pb(x) push_back(x)
#define ll long long
#define pii pair<int, int>
using namespace std;
const int N = 1e5 + 5, Ns4 = 200005;
int n;
long long ans[N];
long long dpx[N], val[N];
int sz[Ns4];
long long dd[Ns4][2];
vector<pii> S[N];
 
void DFS(int u, int p, int max_sz) {
  int now_sz = min(sz[u], max_sz), w = 0;
  vector<int> Q;
  long long sum = 0, pre_sum = 0;
  for (auto [c, v] : S[u])
    if (v != p) {
      DFS(v, u, max_sz);
      long long xx = dd[v][1] + c;
      long long yy = dd[v][0];
      sum += xx;
      if (yy - xx < 0)
        Q.push_back(yy - xx);
      else
        w++;
    }
  for (int i = 0; i <= min(w, 1); i++) Q.pb(0);
  now_sz = min(now_sz, (int)Q.size());
  pre_sum = 1e15;
  //random_shuffle(Q.begin(), Q.end());
  if (now_sz) {
    nth_element(Q.begin(), Q.begin() + now_sz - 1, Q.end());
    int alta = now_sz - 1;
    int x = now_sz;
    for (auto X : Q) {
      if (X < alta) {
        x--;
        pre_sum = sum;
        sum += min(0, X);
      }
    }
    for (auto X : Q) {
      if (X == alta && x) {
        x--;
        pre_sum = sum;
        sum += min(0, X);
      }
    }
    Q.clear();
  }
  if (now_sz < max_sz) pre_sum = sum;
  dd[u][0] = pre_sum;
  dd[u][1] = sum;
}
void calc(int i) {
  DFS(0, 0, i);
  ans[i] = dd[0][1];
}
void dnc(int l = 1, int r = n - 2, ll L = ans[n - 1], ll R = ans[0]) {
  if (l > r) return;
  if (L == R) {
    for (int i = l; i <= r; i++) ans[i] = L;
    return;
  }
  int tm = (l + r) / 2;
  calc(tm);
  dnc(l, tm - 1, ans[tm], R);
  dnc(tm + 1, r, L, ans[tm]);
}
void sub34() {
  REP(i, 0, n) {
    sz[i] = S[i].size() - 1;
    if (i == 0) ++sz[i];
  }
  calc(0);
  calc(n - 1);
  if (1 <= n - 2) dnc();
}
 
vector<long long> minimum_closure_costs(int N, vector<int> U, vector<int> V,
                                        vector<int> W) {
  n = N;
  REP(i, 0, n - 1) {
    S[U[i]].emplace_back(W[i], V[i]);
    S[V[i]].emplace_back(W[i], U[i]);
  }
  sub34();
  vector<long long> ret(n);
  REP(i, 0, n) ret[i] = ans[i];
  return ret;
}

Compilation message (stderr)

roads.cpp: In function 'void DFS(int, int, int)':
roads.cpp:22:13: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   22 |   for (auto [c, v] : S[u])
      |             ^

• Subtask 1: 0 / 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