minic/test/collatz.c

   1 void *malloc();
   2
   3 main()
   4 {
   5         int n;
   6         int nv;
   7         int c;
   8         int cmax;
   9         int *mem;
  10
  11         mem = malloc(sizeof(int) * 4000);
  12
  13         cmax = 0;
  14         for (nv = 1; nv < 1000; nv++) {
  15                 n = nv;
  16                 c = 0;
  17                 while (n != 1) {
  18                         if (n < nv) {
  19                                 c = c + mem[n];
  20                                 break;
  21                         }
  22                         if (n & 1)
  23                                 n = 3*n + 1;
  24                         else
  25                                 n = n / 2;
  26                         c++;
  27                 }
  28                 mem[nv] = c;
  29                 if (c > cmax)
  30                         cmax = c;
  31         }
  32         printf("should print 178: %d\n", cmax);
  33 }