Submission #1046276

#	Time	Username	Problem	Language	Result	Execution time	Memory
1046276		sleepntsheep	File Paths (BOI15_fil)	C11	0 / 100	116 ms	620 KiB

fil

#include <stdio.h>
#include <stdlib.h>

#define N 6005

int n_, s, n, m, k, m_, par[N], *eh[N], eo[N], dep[N], chain[N], o;

int cc(const void *i, const void *j) {
  return *(int*)i-*(int*)j;
}

void pus(int i, int j) {
  int o = eo[i]++;
  if (!o) eh[i] = (int*)malloc(sizeof **eh * 2);
  else if (0 == (o & o - 1)) eh[i] = (int*)realloc(eh[i], 2 * o * sizeof **eh);
  eh[i][o] = j;
}

void efs(int u) {
  dep[u] = 1e9;
  for (int j = 0; j < eo[u]; j += 2) if (eh[u][j] != par[u])
    efs(eh[u][j]);
}

void dfs(int u) {
  for (int j = 0; j < eo[u]; j += 2) if (eh[u][j] != par[u]) {
    int v = eh[u][j], l = eh[u][j+1];
    dep[v] = l + dep[u];
    if (dep[v] > k)
      efs(v);
    else
      dfs(v);
  }
}

int main(void) {
  scanf("%d%d%d%d", &n, &m, &k, &s);
  n_ = n;
  m_ = m;
  n = n + m;
  ++s;

  for (int p, l, i = 1; i <= n; ++i) {
    scanf("%d%d", &p, &l);
    pus(par[i] = p, i);
    pus(p, l + 1);
  }

  dfs(0);

  /* sub 2 */
  for (int i = n_ + 1; i <= n; ++i) {
    if (dep[i] == k) {
      puts("YES");
      continue;
    }

    o = 0;
    for (int cur = i; cur != 0; cur = par[cur])
      if (cur <= n_)
        chain[o++] = dep[i] - dep[cur];
    chain[o++] = dep[i];

    qsort(chain, o, sizeof *chain, cc);

    for (int j = 1; j <= n_; ++j) {
      if (dep[j] + s > k)
        continue;
      int left = k - s - dep[j];

      int md, lb = 0, ub = o;
      while (ub - lb > 1)
        if (chain[md = lb + (ub - lb) / 2] <= left) lb = md;
        else ub = md;
      if (chain[lb] == left) {
        puts("YES");
        goto Next;
      }
    }


    puts("NO");
Next:;
  }
}

Compilation message (stderr)

fil.c: In function 'pus':
fil.c:15:24: warning: suggest parentheses around '-' in operand of '&' [-Wparentheses]
   15 |   else if (0 == (o & o - 1)) eh[i] = (int*)realloc(eh[i], 2 * o * sizeof **eh);
      |                      ~~^~~
fil.c: In function 'main':
fil.c:37:3: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   37 |   scanf("%d%d%d%d", &n, &m, &k, &s);
      |   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
fil.c:44:5: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   44 |     scanf("%d%d", &p, &l);
      |     ^~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 33
• Subtask 2: 0 / 33
• Subtask 3: 0 / 34