Euler 14

#include <stdio.h>

int collatz_len(unsigned long n) {
  int c = 0;
  while (n != 1) {
    if (n % 2 == 1) { 
      n = 3 * n + 1;
    } else {
      n /= 2;
    }
    c++;
  }
  return c;
}

int main() {
  int res = 0, resCount = 0;
  for (int n = 1; n <= 1000000; n++) {
    int c = collatz_len(n);
    if (resCount < c) {
       resCount = c;
       res = n;
    }
  }
  printf("%d %d\n", res, resCount);
}