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  1. #include <stdlib.h>
  2. #include <stdio.h>
  3.  
  4. int main (int argc, char *argv[]) {
  5.     int n = 100000;
  6.     int *result = malloc((n+1) * sizeof(int));
  7.     for (int i = 1; i <= n; i++) {
  8.         result[i] = -1;
  9.     }
  10.     for (int i = 1; i <= n; i++) {
  11.         int s = 0;
  12.         for (long x = i; x != 1; s++) {
  13.             if (x <= n && result[x] != -1) {
  14.                 s += result[x];
  15.                 break;
  16.             }
  17.             x = (x % 2 == 0) ? x / 2 : 3 * x + 1;
  18.         }
  19.         result[i] = s;
  20.     }
  21.     int max = 0;
  22.     for (int i = 1; i <= n; i++) {
  23.         if (max < result[i]) {
  24.             max = result[i];
  25.         }
  26.     }
  27.     printf("%d\n", max);
  28. }
Success #stdin #stdout 0.02s 2068KB
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https://ideone.com/q8YIz2
language:
C99 (gcc 8.3)
created:
12 years ago
visibility:
secret

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