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답안 #877252

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
877252 2023-11-23T04:59:15 Z huutuan Pastiri (COI20_pastiri) C++14
31 / 100
 1000 ms 129720 KB 
#include<bits/stdc++.h>
#define taskname "sheep"

using namespace std;

const int inf=1e9;

struct Node{
   int val, lazy;
   Node (int a=inf, int b=0): val(a), lazy(b){}
   friend Node operator+(const Node &a, const Node &b){
      return Node(min(a.val, b.val));
   }
};

struct SegmentTree{
   int n;
   vector<Node> t;
   void init(int _n){
      n=_n;
      t.assign(4*n+1, Node());
   }
   void build(int k, int l, int r, int *a){
      if (l==r){
         t[k]=Node(a[l]);
         return;
      }
      int mid=(l+r)>>1;
      build(k<<1, l, mid, a);
      build(k<<1|1, mid+1, r, a);
      t[k]=t[k<<1]+t[k<<1|1];
   }
   void apply(int k, int val){
      t[k].val+=val;
      t[k].lazy+=val;
   }
   void push(int k){
      apply(k<<1, t[k].lazy);
      apply(k<<1|1, t[k].lazy);
      t[k].lazy=0;
   }
   void point_update(int k, int l, int r, int pos, int val){
      if (l==r){
         t[k]=Node(val);
         return;
      }
      push(k);
      int mid=(l+r)>>1;
      if (pos<=mid) point_update(k<<1, l, mid, pos, val);
      else point_update(k<<1|1, mid+1, r, pos, val);
      t[k]=t[k<<1]+t[k<<1|1];
   }
   void update(int k, int l, int r, int L, int R, int val){
      if (r<L || R<l) return;
      if (L<=l && r<=R){
         apply(k, val);
         return;
      }
      push(k);
      int mid=(l+r)>>1;
      update(k<<1, l, mid, L, R, val);
      update(k<<1|1, mid+1, r, L, R, val);
      t[k]=t[k<<1]+t[k<<1|1];
   }
   int walk(int k, int l, int r, int val){
      if (l==r) return l;
      push(k);
      int mid=(l+r)>>1;
      if (t[k<<1].val==val) return walk(k<<1, l, mid, val);
      return walk(k<<1|1, mid+1, r, val);
   }
} st;

const int N=5e5+1;
int n, k, a[N], dist[N], best[N], tin[N], tout[N], tdfs, f[N], vis[N], tour[N];
vector<int> g[N], trace[N], gg[N];

void pre_dfs(int u, int p){
   tin[u]=++tdfs;
   tour[tdfs]=u;
   for (int v:g[u]) if (v!=p){
      dist[v]=dist[u]+1;
      pre_dfs(v, u);
   }
   tout[u]=tdfs;
}

void dfs(int u, int p){
   best[u]=st.t[1].val;
   vector<int> idx;
   while (st.t[1].val==best[u]){
      idx.push_back(st.walk(1, 1, n, best[u]));
      st.point_update(1, 1, n, idx.back(), inf);
      trace[u].push_back(tour[idx.back()]);
   }
   for (int i:idx) st.point_update(1, 1, n, i, best[u]);
   for (int v:g[u]) if (v!=p){
      st.update(1, 1, n, 1, n, 1);
      st.update(1, 1, n, tin[v], tout[v], -2);
      dfs(v, u);
      st.update(1, 1, n, tin[v], tout[v], 2);
      st.update(1, 1, n, 1, n, -1);
   }
}

int32_t main(){
   ios_base::sync_with_stdio(false);
   cin.tie(nullptr);
   // freopen(taskname".inp", "r", stdin);
   // freopen(taskname".out", "w", stdout);
   cin >> n >> k;
   bool sub1=1;
   for (int i=1; i<n; ++i){
      int u, v; cin >> u >> v;
      sub1&=abs(u-v)==1;
      g[u].push_back(v);
      g[v].push_back(u);
   }
   for (int i=1; i<=k; ++i){
      int x; cin >> x;
      a[x]=1;
   }
   if (sub1){
      vector<int> v;
      for (int i=1; i<=n; ++i) if (a[i]) v.push_back(i);
      vector<int> ans;
      for (int i=0; i<k; ++i){
         if (i+1<k && (v[i+1]-v[i])%2==0){
            ans.push_back((v[i+1]+v[i])/2);
            ++i;
         }else ans.push_back(v[i]);
      }
      cout << ans.size() << '\n';
      for (int i:ans) cout << i << ' ';
      return 0;
   }
   pre_dfs(1, 0);
   st.init(n);
   for (int i=1; i<=n; ++i){
      if (a[i]) st.point_update(1, 1, n, tin[i], dist[i]);
   }
   for (int i=1; i<=n; ++i){
      if (a[i]) st.point_update(1, 1, n, tin[i], dist[i]);
   }
   dfs(1, 0);
   for (int i=1; i<=n; ++i){
      sort(trace[i].begin(), trace[i].end(), [&](int x, int y){
         return dist[x]<dist[y];
      });
      for (int j:trace[i]) gg[j].push_back(i);
   }
   set<pair<pair<int, int>, int>> st;
   for (int i=1; i<=n; ++i) if (trace[i].size()) st.insert({{dist[trace[i].back()], -dist[i]}, i});
   vector<int> real;
   while (st.size()){
      int idx=st.rbegin()->second; st.erase(prev(st.end()));
      real.push_back(idx);
      vis[idx]=1;
      for (int j:trace[idx]) if (!vis[j]){
         vis[j]=1;
         for (int l:gg[j]) if (trace[l].size() && l!=idx){
            st.erase({{dist[trace[l].back()], -dist[l]}, l});
            while (trace[l].size() && vis[trace[l].back()]) trace[l].pop_back();
            if (trace[l].size()) st.insert({{dist[trace[l].back()], -dist[l]}, l});
         }
      }
      trace[idx].clear();
   }
   cout << real.size() << '\n';
   for (int i:real) cout << i << ' ';
   return 0;
}

Subtask #1
8.0 / 8.0

# 결과 실행 시간 메모리 Grader output
1 Correct 96 ms 55132 KB Output is correct
2 Correct 101 ms 56200 KB Output is correct
3 Correct 97 ms 56336 KB Output is correct
4 Correct 142 ms 61380 KB Output is correct

Subtask #2
0 / 18.0

# 결과 실행 시간 메모리 Grader output
1 Correct 17 ms 46428 KB Output is correct
2 Correct 15 ms 46428 KB Output is correct
3 Execution timed out 1088 ms 129720 KB Time limit exceeded
4 Halted 0 ms 0 KB -

Subtask #3
23.0 / 23.0

# 결과 실행 시간 메모리 Grader output
1 Correct 14 ms 45912 KB Output is correct
2 Correct 12 ms 45916 KB Output is correct
3 Correct 12 ms 45948 KB Output is correct
4 Correct 11 ms 46168 KB Output is correct
5 Correct 12 ms 46172 KB Output is correct
6 Correct 12 ms 46168 KB Output is correct
7 Correct 11 ms 45976 KB Output is correct
8 Correct 12 ms 45956 KB Output is correct
9 Correct 13 ms 46168 KB Output is correct
10 Correct 12 ms 46188 KB Output is correct
11 Correct 25 ms 46268 KB Output is correct
12 Correct 13 ms 46048 KB Output is correct
13 Correct 64 ms 47700 KB Output is correct
14 Correct 12 ms 46172 KB Output is correct
15 Correct 12 ms 46172 KB Output is correct

Subtask #4
0 / 51.0

# 결과 실행 시간 메모리 Grader output
1 Execution timed out 1050 ms 118704 KB Time limit exceeded
2 Halted 0 ms 0 KB -