Submission #1067315

#	Time	Username	Problem	Language	Result	Execution time	Memory
1067315		lmaobruh	Untitled (POI11_rot)	C++14	63 / 100	47 ms	37380 KiB

Main

#include <bits/stdc++.h>
using namespace std;
#define pb emplace_back
#define ll long long
const int N = 2e5+5, sizeBit = 2e5+5;

int ft[sizeBit];

int get(int p) {
  int tot = 0;
  for (; p <= N; p += p & -p)
    tot += ft[p];
  return tot;
}

void upd(int p, int v) {
  for (; p; p -= p & -p)
    ft[p] += v;
}

int n, a[N], curr = 1, sz[N], big[N];
vector<int> g[N];
ll ans[N], inv;

void read() {
  int x;
  cin >> x;
  if (x) return a[curr] = x, void();
  int tmp = curr;
  g[tmp].pb(++curr); g[curr].pb(tmp);
  read(); // cay con trai
  g[tmp].pb(++curr); g[curr].pb(tmp);
  read(); // cay con phai
}

void dfs_sz(int u, int pre = -1) {
  sz[u] = (a[u] > 0); big[u] = 0;
  for (int v : g[u]) if (v != pre) {
    dfs_sz(v, u);
    sz[u] += sz[v];
    if (sz[v] > sz[big[u]]) big[u] = v;
  }
}

void add_inv(int u, int pre) {
  if (a[u]) {
    inv += get(a[u]+1);
    return;
  }
  for (int v : g[u]) if (v != pre)
    add_inv(v, u);
}

void add_bit(int u, int pre) {
  if (a[u]) {
    upd(a[u], 1);
    return;
  }
  for (int v : g[u]) if (v != pre)
    add_bit(v, u);
}

void del(int u, int pre) {
  if (a[u]) {
    upd(a[u], -1);
    return;
  }
  for (int v : g[u]) if (v != pre)
    del(v, u);
}

void add(int u, int pre) {
  add_inv(u, pre);
  add_bit(u, pre);
}

void dfs(int u, int pre) {
  if (a[u]) {
    add(u, pre);
    return;
  }
  int node;
  for (int v : g[u]) if (v != pre && v != big[u]) {
    dfs(v, u);
    ans[u] += ans[v];
    del(v, u);
    node = v;
  }
  dfs(big[u], u);
  ans[u] += ans[big[u]];
  inv = 0; add(node, u);
  ans[u] += min(inv, 1LL * sz[big[u]] * sz[node] - inv);
}

int main() {
  cin.tie(0)->sync_with_stdio(0);
  cin >> n; read();
  dfs_sz(1, 1); dfs(1, 1);
  cout << ans[1];
}

Compilation message (stderr)

rot.cpp: In function 'void dfs(int, int)':
rot.cpp:92:48: warning: 'node' may be used uninitialized in this function [-Wmaybe-uninitialized]
   92 |   ans[u] += min(inv, 1LL * sz[big[u]] * sz[node] - inv);
      |                                         ~~~~~~~^

• Subtask 1: 9 / 9
• Subtask 2: 9 / 9
• Subtask 3: 9 / 9
• Subtask 4: 9 / 9
• Subtask 5: 9 / 9
• Subtask 6: 9 / 9
• Subtask 7: 9 / 9
• Subtask 8: 0 / 9
• Subtask 9: 0 / 9
• Subtask 10: 0 / 9
• Subtask 11: 0 / 10