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  1. // ROOT : DRAGON3012009
  2. #include <bits/stdc++.h>
  3. #define ll long long
  4. #define ld long double
  5. #define el "\n"
  6. #define fast ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
  7. #define __ROOT__ int main()
  8. #pragma GCC optimize("O2")
  9. #define FOR(i,l,r) for(int i = l ; i <= r ; i ++)
  10. #define FORD(i,r,l) for(int i = r ; i >= l ; i --)
  11. #define REP(i, a ) for(int i = 0 ; i < a ; i ++ )
  12. #define fi first
  13. #define se second
  14. #define M 1000000007
  15. #define MAXN 1000001
  16. #define INF (1ll<<30)
  17. #define BLOCK_SIZE 425
  18. #define MAX_NODE 1001001
  19. #define LOG 19
  20. #define ALPHA_SIZE 26
  21. #define BASE 311
  22. #define NAME "file"
  23. #define compare(v) sort((v).begin(), (v).end()); (v).erase(unique((v).begin(), (v).end()), (v).end());
  24. using namespace std;
  25. const ll MOD[] = {(ll)1e9 + 2277, (ll)1e9 + 5277, (ll)1e9 + 8277, (ll)1e9 + 9277, (ll) 1e9 + 7 };
  26. const ll NMOD = 1;
  27. const int dx[] = {-1, 0, 1,0};
  28. const int dy[] = {0, 1, 0, -1};
  29. //**Variable**//
  30. ll n, q;
  31. vector<ll> adj[MAXN];
  32. vector<ll> used, temp;
  33. ll d[MAXN];
  34. ll tin[MAXN], tout[MAXN], euler[2 * MAXN], high[2 * MAXN];
  35. ll st[2 * MAXN][LOG + 1];
  36. ll time_dfs = 0;
  37. //**Struct**//
  38.  
  39. //**Function**//
  40. template<class X, class Y>
  41. bool minimize(X &x, const Y &y) {
  42.     return x > y ? x = y, 1 : 0;
  43. }
  44. template<class X, class Y>
  45. bool maximize(X &x, const Y &y) {
  46.     return x < y ? x = y, 1 : 0;
  47. }
  48.  
  49. void dfs_lca(ll u, ll p, ll h = 0) {
  50.     tin[u] = ++time_dfs;
  51.     euler[time_dfs] = u;
  52.     high[time_dfs] = h;
  53.     for (ll v : adj[u]) if (v != p) {
  54.         dfs_lca(v, u, h + 1);
  55.         euler[++time_dfs] = u;
  56.         high[time_dfs] = h;
  57.     }
  58.     tout[u] = time_dfs;
  59. }
  60.  
  61. void build_sparse() {
  62.     FOR(i, 1, time_dfs) st[i][0] = i;
  63.     FOR(j, 1, LOG) {
  64.         for (int i = 1; i + (1 << j) - 1 <= time_dfs; ++i) {
  65.             int l = st[i][j - 1];
  66.             int r = st[i + (1 << (j - 1))][j - 1];
  67.             st[i][j] = (high[l] < high[r] ? l : r);
  68.         }
  69.     }
  70. }
  71.  
  72. ll get_lca(ll u, ll v) {
  73.     ll l = tin[u], r = tin[v];
  74.     if (l > r) swap(l, r);
  75.     int k = __lg(r - l + 1);
  76.     int lidx = st[l][k], ridx = st[r - (1 << k) + 1][k];
  77.     return euler[high[lidx] < high[ridx] ? lidx : ridx];
  78. }
  79.  
  80. ll get_dist(ll u, ll v) {
  81.     ll lca = get_lca(u, v);
  82.     return high[tin[u]] + high[tin[v]] - 2 * high[tin[lca]];
  83. }
  84.  
  85. void bfs() {
  86.     for (ll u : temp) used.push_back(u);
  87.     temp.clear();
  88.  
  89.     memset(d, 0, sizeof d);
  90.     queue<ll> q;
  91.     for (ll u : used) {
  92.         q.push(u);
  93.         d[u] = 1;
  94.     }
  95.  
  96.     while (!q.empty()) {
  97.         ll u = q.front(); q.pop();
  98.         for (ll v : adj[u]) {
  99.             if (!d[v]) {
  100.                 d[v] = d[u] + 1;
  101.                 q.push(v);
  102.             }
  103.         }
  104.     }
  105. }
  106.  
  107. void init() {
  108.     cin >> n >> q;
  109.     FOR(i, 1, n - 1) {
  110.         ll x, y; cin >> x >> y;
  111.         adj[x].push_back(y);
  112.         adj[y].push_back(x);
  113.     }
  114.     dfs_lca(1, 0);
  115.     build_sparse();
  116.     temp.push_back(1);
  117.     bfs();
  118. }
  119. void solve() {
  120.     FOR(i, 1, q) {
  121.         ll t, u;
  122.         cin>> t>> u;
  123.         if (t == 1) {
  124.             temp.push_back(u);
  125.             if ((int)temp.size() >= BLOCK_SIZE) bfs();
  126.         } else {
  127.             ll ans =  d[u] - 1 ;
  128.             for (ll v : temp) minimize(ans, get_dist(u, v));
  129.             cout << ans << el;
  130.         }
  131.     }
  132. }
  133.  
  134. __ROOT__ {
  135.     // freopen("NAME.inp", "r", stdin);
  136.     // freopen("NAME.out", "w", stdout);
  137.     fast;
  138.     int t = 1; // cin >> t;
  139.     while (t--) {
  140.         init();
  141.         solve();
  142.     }
  143. }
  144.  
Success #stdin #stdout 0.02s 44452KB
comments (?)
stdin 
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stdout 
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https://ideone.com/V4p1QQ
language:
C++14 (clang 8.0)
created:
175 days ago
visibility:
secret

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