Submission #957135

#	Time	Username	Problem	Language	Result	Execution time	Memory
957135		NeroZein	Jail (JOI22_jail)	C++17	61 / 100	5029 ms	31840 KiB

jail

#include "bits/stdc++.h"
using namespace std;

#ifdef Nero
#include "Deb.h"
#else
#define debug(...)
#endif

const int LOG = 18;
const int N = 120005;

int dep[N];
int vis[N];
int pr[LOG][N];
int a[N], b[N];
vector<int> g[N], t[N];

void dfs(int v, int p) {
  for (int u : g[v]) {
    if (u == p) continue; 
    dep[u] = dep[v] + 1; 
    pr[0][u] = v;
    for (int j = 1; j < LOG; ++j) {
      pr[j][u] = pr[j - 1][pr[j - 1][u]];
    }
    dfs(u, v);
  }
}

int lca(int u, int v) {
  if (dep[u] < dep[v]) swap(u, v);
  for (int j = 0; j < LOG; ++j) {
    if ((dep[u] - dep[v]) >> j & 1) {
      u = pr[j][u];
    }
  }
  if (u == v) return v;
  for (int j = LOG - 1; j >= 0; --j) {
    if (pr[j][u] != pr[j][v]) {
      u = pr[j][u], v = pr[j][v];
    }
  }
  return pr[0][v];
}

int onPath(int x, int y, int z) {
  int lc1 = lca(x, y);
  int lc2 = lca(x, z);
  int lc3 = lca(y, z);
  return (lc1 ^ lc2 ^ lc3) == z; 
}

bool dfs2(int v) {
  if (vis[v] == 1) return true; 
  if (vis[v] == 2) return false; 
  vis[v] = 1;
  bool ret = false; 
  for (int u : t[v]) {
    ret |= dfs2(u); 
  }
  vis[v] = 2; 
  return ret; 
}

int main() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  int tt;
  cin >> tt;
  while (tt--) {
    int n;
    cin >> n;
    for(int i = 0; i < n - 1; ++i) {
      int u, v;
      cin >> u >> v;
      g[u].push_back(v);
      g[v].push_back(u);
    }
    int m;
    cin >> m;
    for (int i = 1; i <= m; ++i) {
      cin >> a[i] >> b[i];
    }
    dfs(1, 0);
    for (int i = 1; i <= m; ++i) {
      for (int j = 1; j <= m; ++j) {
        if (i == j) continue; 
        if (onPath(a[i], b[i], a[j])) {
          t[j].push_back(i);
        }
        if (onPath(a[i], b[i], b[j])) {
          t[i].push_back(j);
        }
      }
    }
    bool cycle = false; 
    for (int i = 1; i <= m; ++i) {
      cycle |= dfs2(i);
    }
    cout << (cycle ? "No" : "Yes") << '\n';  
    fill(vis + 1, vis + 1 + m, 0);
    fill(t + 1, t + 1 + m, vector<int>());
    fill(g + 1, g + 1 + n, vector<int>());
  }
  return 0;
}

• Subtask 1: 0 / 5
• Subtask 2: 5 / 5
• Subtask 3: 16 / 16
• Subtask 4: 28 / 28
• Subtask 5: 12 / 12
• Subtask 6: 0 / 11
• Subtask 7: 0 / 23