Submission #854005

#	Time	Username	Problem	Language	Result	Execution time	Memory
854005		mychecksedad	Inside information (BOI21_servers)	C++17	50 / 100	234 ms	128192 KiB

servers

/* Author : Mychecksdead  */
#include<bits/stdc++.h>
using namespace std;
#define ll long long int
#define MOD (1000000000+7)
#define MOD1 (998244353)
#define pb push_back
#define all(x) x.begin(), x.end()
#define en cout << '\n'
const int N = 1e6+100, M = 1e5+10, K = 22;

struct Edge{
  int to, tm;
};
struct Query{
  int a, b, tm, ans;
};

int n, k, timer = 0, dep[N], up[N][K], tin[N], tout[N];
array<int, 3> I[N][K], D[N][K];
vector<Edge> g[N];
void dfs(int v, int p){
  tin[v] = timer++;
  dep[v] = dep[p] + 1;
  up[v][0] = p;
  for(auto e: g[v]){
    int u = e.to;
    
    if(u != p){
      I[u][0] = {
        e.tm,
        e.tm,
        1
      };
      D[u][0] = {
        e.tm,
        e.tm,
        1
      };
      dfs(u, v);
    }
  }
  tout[v] = timer++;
}
bool is_ancestor(int u, int v){
  return tin[u] <= tin[v] && tout[v] <= tout[u];
}
int _lca(int u, int v){
  if(is_ancestor(u, v)) return u;
  if(is_ancestor(v, u)) return v;
  for(int j = K-1; j >= 0; --j)
    if(!is_ancestor(up[u][j], v)) u = up[u][j];
  return up[u][0];
}

void solve(){
  cin >> n >> k;
  vector<Query> Q;
  for(int i = 1; i < n + k; ++i){
    char tp; cin >> tp;
    int u, v; cin >> u >> v;
    if(tp == 'S'){
      g[u].pb({v, i});
      g[v].pb({u, i});
    }else Q.pb({u, v, i, 0});
  }

  dep[1] = 0;
  dfs(1, 1);
  
  for(int j = 1; j < K; ++j)
    for(int i = 1; i <= n; ++i){
      up[i][j] = up[up[i][j - 1]][j - 1];
      
      I[i][j] = {
        min(I[i][j - 1][0], I[up[i][j - 1]][j - 1][0]),
        max(I[i][j - 1][1], I[up[i][j - 1]][j - 1][1]),
        I[i][j - 1][2] && I[up[i][j - 1]][j - 1][2] && (I[i][j - 1][1] < I[up[i][j - 1]][j - 1][0])
      };

      D[i][j] = {
        min(D[i][j - 1][0], D[up[i][j - 1]][j - 1][0]),
        max(D[i][j - 1][1], D[up[i][j - 1]][j - 1][1]),
        D[i][j - 1][2] && D[up[i][j - 1]][j - 1][2] && (D[i][j - 1][0] > D[up[i][j - 1]][j - 1][1])
      };
    }

  for(auto &q: Q){
    int u = q.a, v = q.b;
    int lca = _lca(u, v);

    // v to lca increasing, u to lca decreasin
    int lastu = -1, lastv = -1, mx = 0;
    bool ok = 1;

    for(int j = K - 1; j >= 0; --j){

      if((dep[v] - dep[lca]) & (1<<j)){
        mx = max(mx, I[v][j][1]);
        ok &= I[v][j][2];
        if(lastv == -1){
          lastv = I[v][j][1];
        }else if(lastv < I[v][j][0]){
          lastv = I[v][j][1];
        }else ok = 0;

        v = up[v][j];
      }

      if((dep[u] - dep[lca]) & (1<<j)){
        mx = max(mx, D[u][j][1]);
        ok &= D[u][j][2];
        if(lastu == -1){
          lastu = D[u][j][0];
        }else if(lastu > D[u][j][1]){
          lastu = D[u][j][0];
        }else ok = 0;

        u = up[u][j];
      }
    }
    if(ok && lastu != -1 && lastv != -1){
      ok = lastu > lastv;
    }
    if(ok && mx > q.tm) ok = 0;
    q.ans = ok;
  }



  for(auto q: Q) cout << (q.ans ? "yes\n" : "no\n");
}


int main(){
  cin.tie(0); ios::sync_with_stdio(0);
  int tt = 1, aa;
  // freopen("in.txt", "r", stdin);
  // freopen("out.txt", "w", stdout);
  while(tt--){
    solve();
  }
  cerr<<"time taken : "<<(float)clock()/CLOCKS_PER_SEC<<" seconds\n";
  return 0;
} 

Compilation message (stderr)

servers.cpp: In function 'int main()':
servers.cpp:137:15: warning: unused variable 'aa' [-Wunused-variable]
  137 |   int tt = 1, aa;
      |               ^~

• Subtask 1: 2.5 / 2.5
• Subtask 2: 0 / 2.5
• Subtask 3: 2.5 / 2.5
• Subtask 4: 0 / 2.5
• Subtask 5: 5 / 5
• Subtask 6: 0 / 5
• Subtask 7: 10 / 10
• Subtask 8: 0 / 10
• Subtask 9: 12.5 / 12.5
• Subtask 10: 0 / 12.5
• Subtask 11: 17.5 / 17.5
• Subtask 12: 0 / 17.5