test/yosupo/Tree/Jump-on-Tree.test.cpp

View this file on GitHub
Last update: 2023-11-12 01:15:26+09:00
Problem: https://judge.yosupo.jp/problem/jump_on_tree

Depends on

Code

#define PROBLEM "https://judge.yosupo.jp/problem/jump_on_tree"

#include "../../../template/template.hpp"

#include "../../../graph/lca.hpp"
#include "../../../others/fastIO.hpp"

int main(){
  int n,q;
  cin >> n >> q;
  vvi root(n);
  rep(i, n - 1){
    int a,b;
    cin >> a >> b;
    root[a].push_back(b);
    root[b].push_back(a);
  }
  const lca<vvi> g(root);
  rep(_, q){
    int s,t,k;
    cin >> s >> t >> k;
    cout << g.jump(s, t, k) << '\n';
  }
}

#line 1 "test/yosupo/Tree/Jump-on-Tree.test.cpp"
#define PROBLEM "https://judge.yosupo.jp/problem/jump_on_tree"

#line 1 "template/template.hpp"
#include <iostream>
#include <cmath>
#include <string>
#include <vector>
#include <algorithm>
#include <tuple>
#include <cstdint>
#include <cstdio>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <deque>
#include <bitset>
#include <cctype>
#include <climits>
#include <functional>
#include <cassert>
#include <numeric>
#include <cstring>
#define rep(i, n) for(int i = 0; i < (n); i++)
#define per(i, n) for(int i = (n) - 1; i >= 0; i--)
using ll = long long;
#define vi vector<int>
#define vvi vector<vi>
#define vl vector<ll>
#define pii pair<int, int>
#define pll pair<ll, ll>
#define all(a) (a).begin(), (a).end()
#define rall(a) (a).rbegin(), (a).rend()
constexpr int mod = 1000000007;
using namespace std;
template<class T, class U>
bool chmax(T &a, const U &b){ return a < b ? (a = b, 1) : 0; }
template<class T, class U>
bool chmin(T &a, const U &b){ return a > b ? (a = b, 1) : 0; }
#line 4 "test/yosupo/Tree/Jump-on-Tree.test.cpp"

#line 1 "graph/lca.hpp"
template <class graph>
struct lca {
  const graph &G;
  vector<vector<int>> parent;
  vector<int> dep;
  int log = 1;
  lca(const graph &G, int root = 0) : G(G){
    init(root);
  }
  void init(int root = 0){
    const int n = G.size();
    dep.assign(n, -1);
    parent.assign(1, vector<int>(n, -1));
    queue<int> que({ root });
    dep[root] = 0;
    int max_dep = 0;
    while(!que.empty()){
      const int pos = que.front();
      que.pop();
      max_dep = max(max_dep, dep[pos]);
      for(const auto &x : G[pos]){
        if(dep[x] == -1){
          dep[x] = dep[pos] + 1;
          parent[0][x] = pos;
          que.push(x);
        }
      }
    }
    while((1 << log) <= max_dep) log++;
    parent.resize(log, vector<int>(n, -1));
    for(int k = 0; k < log - 1; k++){
      for(int v = 0; v < n; v++){
        if(parent[k][v] < 0) parent[k + 1][v] = -1;
        else parent[k + 1][v] = parent[k][parent[k][v]];
      }
    }
  }
  int query(int u, int v) const{
    if(dep[u] < dep[v]) swap(u, v);
    const int sub = dep[u] - dep[v];
    for(int k = 0; k < log; k++){
      if(!(sub >> k)) break;
      if(sub >> k & 1) u = parent[k][u];
    }
    if(u == v) return u;
    for(int k = __lg(dep[u]); k >= 0; k--){
      if(parent[k][u] != parent[k][v]){
        u = parent[k][u];
        v = parent[k][v];
      }
    }
    return parent[0][u];
  }
  int dist(const int u, const int v) const{
    return dep[u] + dep[v] - dep[query(u, v)] * 2;
  }
  int jump(int u, int v, int d) const{
    const int lc = query(u, v);
    const int l = dep[u] - dep[lc];
    const int r = dep[v] - dep[lc];
    if(d < 0 || d > l + r) return -1;
    if(l < d){
      d = l + r - d;
      swap(u, v);
    }
    for(int k = 0; k < log; k++){
      if(!(d >> k)) break;
      if(d >> k & 1) u = parent[k][u];
    }
    return u;
  }
};
#line 1 "others/fastIO.hpp"
namespace FastIO {
struct PreCalc {
  char num[10000 * 4];
  constexpr PreCalc() : num(){
    for(int i = 0; i < 10000; i++){
      int t = i;
      for(int j = 3; j >= 0; j--){
        num[i*4 + j] = (t % 10) + '0';
        t /= 10;
      }
    }
  }
};
static constexpr PreCalc pr;
struct FastIO {
  template <class T>
  using enable_if_integer = enable_if_t<is_integral<T>::value || is_same<T, __int128_t>::value || is_same<T, __uint128_t>::value>;
  static constexpr int buf_size = 1 << 20;
  static constexpr int rem = 1 << 6;
  char in_buf[buf_size], *in_cur = in_buf + buf_size;
  char out_buf[buf_size], *out_cur = out_buf;
  FastIO(){ load(); }
  ~FastIO(){ flush(); }
  void load(){
    const int len = in_buf + buf_size - in_cur;
    memmove(in_buf, in_cur, len);
    in_cur = in_buf;
    fread(in_buf + len, 1, buf_size - len, stdin);
  }
  void flush(){
    fwrite(out_buf, 1, out_cur - out_buf, stdout);
    out_cur = out_buf;
  }
  void through(){
    if(in_cur - in_buf >= buf_size - rem) load();
    while(*in_cur <= ' ') in_cur++;
    assert(in_buf <= in_cur && in_cur < in_buf + buf_size);
  }
  #define gc() (*in_cur++)
  template <class T, enable_if_integer<T>* = nullptr>
  inline void read(T &x){
    through();
    bool neg = false;
    int c = gc();
    if(c == '-') neg = true, c = gc();
    x = c^'0'; c = gc();
    while(c >= '0' && c <= '9') x = x*10 + (c^'0'), c = gc();
    if(neg) x = -x;
  }
  inline void read(string &x){
    through();
    x.clear();
    while(true){
      char *p = in_cur;
      while(*p > ' ' && p - in_buf < buf_size - rem) p++;
      copy(in_cur, p, back_inserter(x));
      in_cur = p;
      if(*p <= ' ') break;
      load();
    }
  }
  inline void read(char &x){
    through();
    x = gc();
  }
  #undef gc
  #define pc(c) *out_cur++ = (c)
  template <class T, enable_if_integer<T>* = nullptr>
  inline void out(T x){
    static constexpr int tmp_size = sizeof(T)*5/2;
    static char tmp[tmp_size];
    if(out_cur - out_buf >= buf_size - rem) flush();
    if(!x){ pc('0'); return; }
    if(x < 0){ pc('-'); x = -x; }
    int idx = tmp_size;
    while(x >= 10000){
      idx -= 4;
      memcpy(tmp + idx, pr.num + (x % 10000)*4, 4);
      x /= 10000;
    }
    if(x < 100){
      if(x < 10){
        pc(x + '0');
      }else{
        pc(x/10 + '0');
        pc(x%10 + '0');
      }
    }else{
      if(x < 1000){
        memcpy(out_cur, pr.num + x*4 + 1, 3);
        out_cur += 3;
      }else{
        memcpy(out_cur, pr.num + x*4, 4);
        out_cur += 4;
      }
    }
    memcpy(out_cur, tmp + idx, tmp_size - idx);
    out_cur += tmp_size - idx;
  }
  inline void out(const string &s){
    flush();
    fwrite(s.c_str(), 1, s.size(), stdout);
  }
  inline void out(const char c){
    if(out_cur - out_buf >= buf_size - rem) flush();
    pc(c);
  }
  #undef pc
  template <class T>
  friend FastIO &operator>>(FastIO &io, T &x){
    io.read(x);
    return io;
  }
  template <class T>
  friend FastIO &operator<<(FastIO &io, const T &x){
    io.out(x);
    return io;
  }
};
FastIO io;
} // namespace FastIO

using FastIO::io;
#define cin io
#define cout io
#line 7 "test/yosupo/Tree/Jump-on-Tree.test.cpp"

int main(){
  int n,q;
  cin >> n >> q;
  vvi root(n);
  rep(i, n - 1){
    int a,b;
    cin >> a >> b;
    root[a].push_back(b);
    root[b].push_back(a);
  }
  const lca<vvi> g(root);
  rep(_, q){
    int s,t,k;
    cin >> s >> t >> k;
    cout << g.jump(s, t, k) << '\n';
  }
}