LOJ#6038. 「雅礼集训 2017 Day5」远行 [LCT维护子树的直径]

树的直径一定是原联通块4个里的组合

1.LCT，维护树的直径，这题就做完了

2.直接倍增，lca啥的求求距离，也可以吧…

// powered by c++11
// by Isaunoya
#include <bits/stdc++.h>
#define rep(i, x, y) for (register int i = (x); i <= (y); ++i)
#define Rep(i, x, y) for (register int i = (x); i >= (y); --i)
using namespace std;
using db = double;
using ll = long long;
using uint = unsigned int;
// #define int long long
using pii = pair<int, int>;
#define ve vector
#define Tp template
#define all(v) v.begin(), v.end()
#define sz(v) ((int)v.size())
#define pb emplace_back
#define fir first
#define sec second
// the cmin && cmax
Tp<class T> void cmax(T& x, const T& y) {
  if (x < y) x = y;
}
Tp<class T> void cmin(T& x, const T& y) {
  if (x > y) x = y;
}
// sort , unique , reverse
Tp<class T> void sort(ve<T>& v) { sort(all(v)); }
Tp<class T> void unique(ve<T>& v) {
  sort(all(v));
  v.erase(unique(all(v)), v.end());
}
Tp<class T> void reverse(ve<T>& v) { reverse(all(v)); }
const int SZ = 0x191981;
struct FILEIN {
  ~FILEIN() {}
  char qwq[SZ], *S = qwq, *T = qwq, ch;
  char GETC() { return (S == T) && (T = (S = qwq) + fread(qwq, 1, SZ, stdin), S == T) ? EOF : *S++; }
  FILEIN& operator>>(char& c) {
    while (isspace(c = GETC()))
      ;
    return *this;
  }
  FILEIN& operator>>(string& s) {
    while (isspace(ch = GETC()))
      ;
    s = ch;
    while (!isspace(ch = GETC())) s += ch;
    return *this;
  }
  Tp<class T> void read(T& x) {
    bool sign = 1;
    while ((ch = GETC()) < 0x30)
      if (ch == 0x2d) sign = 0;
    x = (ch ^ 0x30);
    while ((ch = GETC()) > 0x2f) x = x * 0xa + (ch ^ 0x30);
    x = sign ? x : -x;
  }
  FILEIN& operator>>(int& x) { return read(x), *this; }
  // FILEIN& operator>>(signed& x) { return read(x), *this; }
  FILEIN& operator>>(unsigned& x) { return read(x), *this; }
} in;
struct FILEOUT {
  const static int LIMIT = 0x114514;
  char quq[SZ], ST[0x114];
  signed sz, O;
  ~FILEOUT() { sz = O = 0; }
  void flush() {
    fwrite(quq, 1, O, stdout);
    fflush(stdout);
    O = 0;
  }
  FILEOUT& operator<<(char c) { return quq[O++] = c, *this; }
  FILEOUT& operator<<(string str) {
    if (O > LIMIT) flush();
    for (char c : str) quq[O++] = c;
    return *this;
  }
  Tp<class T> void write(T x) {
    if (O > LIMIT) flush();
    if (x < 0) {
      quq[O++] = 0x2d;
      x = -x;
    }
    do {
      ST[++sz] = x % 0xa ^ 0x30;
      x /= 0xa;
    } while (x);
    while (sz) quq[O++] = ST[sz--];
    return;
  }
  FILEOUT& operator<<(int x) { return write(x), *this; }
  // FILEOUT& operator<<(signed x) { return write(x), *this; }
  FILEOUT& operator<<(unsigned x) { return write(x), *this; }
} out;
const int maxn = 3e5 + 10;
int f[maxn];
int find(int x) { return x == f[x] ? x : f[x] = find(f[x]); }
int px[maxn], py[maxn], fa[maxn], sz[maxn], rev[maxn], ch[maxn][2];
#define ls(x) ch[x][0]
#define rs(x) ch[x][1]
bool isroot(int x) { return (x != ls(fa[x])) && (x != rs(fa[x])); }
void pushup(int x) { sz[x] = sz[ls(x)] + sz[rs(x)] + 1; }
void pushr(int x) {
  rev[x] ^= 1;
  swap(ls(x), rs(x));
}
void pushdown(int x) {
  if (!rev[x]) return;
  if (ls(x)) pushr(ls(x));
  if (rs(x)) pushr(rs(x));
  rev[x] = 0;
}
void pushall(int x) {
  if (!isroot(x)) pushall(fa[x]);
  pushdown(x);
}
void rotate(int x) {
  int y = fa[x], z = fa[y], l = (rs(y) == x), r = l ^ 1;
  if (!isroot(y)) ch[z][rs(z) == y] = x;
  fa[x] = z, fa[y] = x;
  fa[ch[x][r]] = y, ch[y][l] = ch[x][r], ch[x][r] = y;
  pushup(y), pushup(x);
}
void splay(int x) {
  pushall(x);
  while (!isroot(x)) {
    int y = fa[x], z = fa[y];
    if (!isroot(y)) rotate(((rs(y) == x) ^ (rs(z) == y)) ? x : y);
    rotate(x);
  }
}
void access(int x) {
  for (int tp = 0; x; tp = x, x = fa[tp]) splay(x), rs(x) = tp, pushup(x);
}
void makeroot(int x) { access(x), splay(x), pushr(x); }
int dis(int x, int y) {
  makeroot(x), access(y), splay(y);
  return sz[y];
}
int qwq[5];
void link(int x, int y) {
  int fx = find(x), fy = find(y);
  int mx = -1, d = 0, rx, ry, cnt = 0;
  makeroot(x), fa[x] = y;
  qwq[++cnt] = px[fx], qwq[++cnt] = py[fx];
  qwq[++cnt] = px[fy], qwq[++cnt] = py[fy];
  for (int i = 1; i <= 4; i++)
    for (int j = i + 1; j <= 4; j++) {
      d = dis(qwq[i], qwq[j]);
      if (d > mx) mx = d, rx = qwq[i], ry = qwq[j];
    }
  f[fx] = fy, px[fy] = rx, py[fy] = ry;
}
int type, n, q, opt, ans = 0;
signed main() {
#ifdef _WIN64
  freopen("testdata.in", "r", stdin);
#else
  ios_base ::sync_with_stdio(false);
  cin.tie(nullptr), cout.tie(nullptr);
#endif
  // code begin.
  in >> type >> n >> q;
  for (int i = 1; i <= n; i++) f[i] = px[i] = py[i] = i, sz[i] = 1;
  while (q--) {
    int opt;
    in >> opt;
    if (opt == 1) {
      int x, y;
      in >> x >> y, x ^= ans, y ^= ans, link(x, y);
    } else {
      int x, fx;
      in >> x, x ^= ans, fx = find(x);
      ans = max(dis(x, px[fx]), dis(x, py[fx]));
      ans--;
      out << ans << '\n';
    }
    if (!type) ans = 0;
  }
  return out.flush(), 0;
  // code end.
}