fork download
copy 
  1. #include <stdlib.h>
  2. #include <stdio.h>
  3. struct vec {int *data, cap, size;};
  4. struct vec vec_alloc(int cap) {
  5.   struct vec v = {0, 0, 0};
  6.   if (0 < cap) v.data = malloc(cap * sizeof (int)), v.cap = cap;
  7.   return v;
  8. }
  9. void vec_free(struct vec v) {free(v.data);}
  10. void vec_push(struct vec *v, int value) {
  11.   if (!v) return;
  12.   void *new_data;
  13.   if (v->cap == v->size) {
  14.     new_data = realloc(v->data, v->cap * 2 * sizeof (int));
  15.     if (!new_data) return;
  16.     v->data = new_data;
  17.     v->cap *= 2;
  18.   }
  19.   v->data[v->size++] = value;
  20. }
  21. struct vec p(struct vec v) {
  22.   int i;
  23.   putchar('[');
  24.   for (i = 0; i < v.size; i++) {
  25.     if (0 < i) printf(", ");
  26.     printf("%d", v.data[i]);
  27.   }
  28.   puts("]");
  29.   return v;
  30. }
  31.  
  32. int collatz(int n) {
  33.   return n % 2 ? n * 3 + 1 : n / 2;
  34. }
  35. struct vec chain(int n) {
  36.   struct vec v = vec_alloc(8);
  37.   do vec_push(&v, n), n = collatz(n); while (1 < v.data[v.size - 1]);
  38.   return v;
  39. }
  40. void f(int n) {
  41.   vec_free(p(chain(n)));
  42. }
  43. int f884(int a, int b, int c) {
  44.   int i, count = 0;
  45.   for (i = a; i <= b; i++) {
  46.     struct vec v = chain(i);
  47.     if (c <= v.size) count++;
  48.     vec_free(v);
  49.   }
  50.   return count;
  51. }
  52. int main() {
  53.   f(10), f(30);
  54.   printf("%d\n", f884(1, 100, 15));
  55.   return 0;
  56. }
  57.  
Success #stdin #stdout 0s 9424KB
comments (?)
stdin
copy 
Standard input is empty
stdout
copy 
[10, 5, 16, 8, 4, 2, 1]
[30, 15, 46, 23, 70, 35, 106, 53, 160, 80, 40, 20, 10, 5, 16, 8, 4, 2, 1]
71
https://ideone.com/jwtvbF
language:
C (gcc 8.3)
created:
5 years ago
visibility:
secret

Share or Embed source code

Discover > Sphere Engine API

The brand new service which powers Ideone!

Discover > IDE Widget

Widget for compiling and running the source code in a web browser!