/tmp/solutions/build/lca-main.cpp:
    1|       |#include <common.h>
    2|       |prelude;
    3|       |
    4|       |namespace {
    5|       |
    6|       |constexpr int N = 5e5;
    7|       |
    8|       |int next[N];
    9|       |int head[N];
   10|       |int size[N];
   11|       |int depth[N];
   12|       |int heavy[N];
   13|       |int ances[N];
   14|       |int parent[N];
   15|       |
   16|   500k|def build_step_1(int u, int d) -> void {
   17|   500k|  size[u] = 1;
   18|   500k|  depth[u] = d;
   19|   999k|  for (int v = head[u]; v; v = next[v]) {
                                         ^499k
  ------------------
  |  Branch (19:25): [True: 50.00%, False: 50.00%]
  ------------------
   20|   499k|    build_step_1(v, d + 1);
   21|   499k|    size[u] += size[v];
   22|   499k|    if (heavy[u] == 0 || size[v] > size[heavy[u]]) {
                                       ^249k
  ------------------
  |  Branch (22:9): [True: 50.00%, False: 50.00%]
  |  Branch (22:26): [True: 0.00%, False: 100.00%]
  ------------------
   23|   250k|      heavy[u] = v;
   24|   250k|    }
   25|   499k|  }
   26|   500k|}
   27|       |
   28|   500k|def build_step_2(int u, int a) -> void {
   29|   500k|  ances[u] = a;
   30|   999k|  for (int v = head[u]; v; v = next[v]) {
                                         ^499k
  ------------------
  |  Branch (30:25): [True: 50.00%, False: 50.00%]
  ------------------
   31|   499k|    if (v != heavy[u]) {
  ------------------
  |  Branch (31:9): [True: 50.00%, False: 50.00%]
  ------------------
   32|   249k|      build_step_2(v, v);
   33|   249k|    }
   34|   499k|  }
   35|   500k|  if (heavy[u]) build_step_2(heavy[u], a);
                              ^250k
  ------------------
  |  Branch (35:7): [True: 50.00%, False: 50.00%]
  ------------------
   36|   500k|}
   37|       |
   38|   500k|def lca(int u, int v) -> int {
   39|   500k|  if (depth[u] < 32 && depth[v] < 32) {
  ------------------
  |  Branch (39:7): [True: 100.00%, False: 0.00%]
  |  Branch (39:24): [True: 100.00%, False: 0.00%]
  ------------------
   40|   695k|    while (depth[u] > depth[v]) {
  ------------------
  |  Branch (40:12): [True: 28.06%, False: 71.94%]
  ------------------
   41|   195k|      u = parent[u];
   42|   195k|    }
   43|   985k|    while (depth[v] > depth[u]) {
  ------------------
  |  Branch (43:12): [True: 49.27%, False: 50.73%]
  ------------------
   44|   485k|      v = parent[v];
   45|   485k|    }
   46|  8.13M|    while (u != v) {
  ------------------
  |  Branch (46:12): [True: 93.85%, False: 6.15%]
  ------------------
   47|  7.63M|      u = parent[u];
   48|  7.63M|      v = parent[v];
   49|  7.63M|    }
   50|   500k|    return u;
   51|   500k|  }
   52|      0|  while (ances[u] != ances[v]) {
  ------------------
  |  Branch (52:10): [True: 0.00%, False: 0.00%]
  ------------------
   53|      0|    if (depth[ances[u]] > depth[ances[v]]) {
  ------------------
  |  Branch (53:9): [True: 0.00%, False: 0.00%]
  ------------------
   54|      0|      u = parent[ances[u]];
   55|      0|    } else {
   56|      0|      v = parent[ances[v]];
   57|      0|    }
   58|      0|  }
   59|      0|  return depth[u] < depth[v] ? u : v;
  ------------------
  |  Branch (59:10): [True: 0.00%, False: 0.00%]
  ------------------
   60|   500k|}
   61|       |
   62|       |} // namespace
   63|       |
   64|      1|int main() {
   65|      1|  rd rd;
   66|      1|  wt wt;
   67|      1|  int n = rd.uh();
   68|      1|  int q = rd.uh();
   69|      1|#ifdef LOCAL
   70|      1|  std::memset(head, 0, 4 * n);
   71|      1|  std::memset(heavy, 0, 4 * n);
   72|      1|  std::memset(parent, 0, 4 * n);
   73|      1|#endif
   74|   500k|  for (int i = 1; i < n; ++i) {
                                       ^499k
  ------------------
  |  Branch (74:19): [True: 100.00%, False: 0.00%]
  ------------------
   75|   499k|    int p = rd.uh();
   76|   499k|    parent[i] = p;
   77|   499k|    next[i] = head[p];
   78|   499k|    head[p] = i;
   79|   499k|  }
   80|      1|  build_step_1(0, 0);
   81|      1|  build_step_2(0, 0);
   82|   500k|  while (q--) {
  ------------------
  |  Branch (82:10): [True: 100.00%, False: 0.00%]
  ------------------
   83|   500k|    int u = rd.uh();
   84|   500k|    int v = rd.uh();
   85|   500k|    int w = lca(u, v);
   86|   500k|    wt.uw(w);
   87|   500k|  }
   88|      1|  return 0;
   89|      1|}