Submission #1020701

#	Time	Username	Problem	Language	Result	Execution time	Memory
1020701		fimh	Untitled (POI11_rot)	C++17	63 / 100	154 ms	46676 KiB

Main

#include <bits/stdc++.h>
using namespace std;
const int MAXN = 1000005, mod = 998244353;
int n;
int hvy[MAXN], ans[MAXN], a[MAXN], dp[MAXN], leave[MAXN];
vector<int> adj[MAXN];

struct FenwickTree{
  int bit[MAXN];
  void upd(int i, int x){
    while (i <= n){
      bit[i] += x;
      i += i & (-i);
    }
  }
  int sum(int i){
    int ans = 0;
    while (i){
      ans += bit[i];
      i -= i & (-i);
    }
    return ans;
  }
  int get(int l, int r){
    if (l > r) return 0;
    return sum(r) - sum(l - 1);
  }
}ft;

int node = 1;
void input(){
  int x; cin >> x;
  a[node] = x;
  if (x) return;
  int nw = node;
  adj[nw].push_back(++node);
  input();
  adj[nw].push_back(++node);
  input();
}

int pre_dfs(int u, int p){
  if (adj[u].empty()) leave[u] = 1;
  int sz = 1, mx = 0;
  for (int v : adj[u]){
    if (v != p){
      int csz = pre_dfs(v, u);
      leave[u] += leave[v];
      sz += csz;
      if (mx < csz){
        mx = csz;
        hvy[u] = v;
      }
    }
  }
  return sz;
}

void ope(int u, int p, int x){
  if (a[u]) ft.upd(a[u], x);
  for (int v : adj[u]){
    if (v != p) ope(v, u, x);
  }
}

int c1, c2;
void calc(int u, int p){
  if (a[u]){
    c1 += ft.get(a[u] + 1, n);
    c2 += ft.get(1, a[u] - 1);
  }
  for (int v : adj[u]){
    if (v != p) calc(v, u);
  }
}

void dfs(int u, int p){
  for (int &v : adj[u]){
    if (v != p && v != hvy[u]){
      dfs(v, u);
      dp[u] += dp[v];
      ope(v, u, -1);
    }
  }
  if (hvy[u]){
    dfs(hvy[u], u);
    dp[u] += dp[hvy[u]];
  }
  c1 = c2 = 0;
  for (int v : adj[u]){
    if (v != p && v != hvy[u]){
      calc(v, u);
    }
  }
  dp[u] += min(c1, c2);
  for (int v : adj[u]){
    if (v != p && v != hvy[u]){
      ope(v, u, 1);
    }
  }
  if (a[u]) ft.upd(a[u], 1);
}

void solve(){
  cin >> n;
  input();
  pre_dfs(1, 1);
  dfs(1, 1);
  cout << dp[1];
}

signed main(){
  ios_base::sync_with_stdio(0);
  cin.tie(0); cout.tie(0);
  int t = 1; // cin >> t;
  while (t--){
    solve();
  }  
}

• 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