Page 46 of 93

Posted: Sun Jan 22, 2006 9:49 pm
by mamun
Your main() function is supposed to return an integer.


Posted: Sun Jan 22, 2006 9:57 pm
by Red Cent
oh ...

like DUH...

Lets see if that works then.

laughing all the way...

Posted: Sun Jan 22, 2006 10:01 pm
by Red Cent

Now it compiles (because I forgot that stupid return statement)


Is my program that inefficient?

Wow - I bow to those who solved this deceivingly simple prob

Posted: Sun Jan 22, 2006 10:48 pm
by Red Cent

I narrowed down what my program was doing.


It's a simple problem that's cursed website owners and commercial enterprises.

I found a test case number (by putting in ranges of test inputs) which I wont reveal here, unless asked of course, that when I put in that number as input, my program would run on forever.

It's because the number would eventually lead to such a high number in 3N+1, that it would overflow and become negative - thus never reaching a solution.


It reminds me of the old news story (help me out if you can remember) where a guy was buying products from a store online. He was putting in a number so big (I dont remember if it was quantity or price), he would be getting products delivered to his door along with a sizeable check (because the price turned out to be negative, he was owed money according to the system).

Basically an employee of the company noticed this and asked (why the **** are we shipping a product to this guy along with a check?)


Back to the drawing board.

Posted: Sun Jan 22, 2006 11:11 pm
by mamun
Well, there's no magical number. From the look of you code (I haven't tested) your program should fail on input like

Code: Select all

10 100
100 10
10 100


Posted: Mon Jan 23, 2006 12:31 am
by Red Cent
I forgot I changed the loop from counter != second number to counter <=secondnumber

making the bigger number entered first not work!



Posted: Mon Jan 23, 2006 11:49 pm
by sclo
this problem is not the easiest problems, if you're new, try some other problems first

100 Compile error 6 times... Help!!

Posted: Tue Feb 07, 2006 7:33 pm
by tellmewhy
my code:
import java.util.*;

class Main
static int Begin(int a, int b, int flag)
int count = 0, cyclelength = 0, c=0;
int temp = b;
if (a>b){
for (int i=a;i<=b;i++,count=0)
if (c%2==1)

if (count>cyclelength)
return cyclelength;

public static void main(String[] args)
int flag = 0;
int i=0;
String[] storedline = new String[1000];
Main TryOne = new Main();
Scanner scanner = new Scanner(;

while (flag!=1)
String getinput = scanner.nextLine();
if (!(getinput.equals("")))
Scanner scanner1 = new Scanner(getinput);
int a = scanner1.nextInt();
int b = scanner1.nextInt();
int temp = TryOne.Begin(a,b,flag);
storedline = a + " " + b + " " + temp;
for (int j=0; j<i; j++)

compile error!! i read the sticky, made amendemnts and still get CE... i suspected it is becos of the Scanner class i used... any help??

Posted: Wed Feb 08, 2006 7:58 am
by chunyi81
Yes. Scanner class is only available in JDK 1.5 and the JDK used in this judge unfortunately is very old, which is JDK 1.1

Posted: Wed Feb 08, 2006 4:43 pm
by f.eliel
I'm getting WA and i can't find the problem. It works just fine when i test it.

Code: Select all

#include <stdio.h>

int main(void)
   long x, a, b, n;
   int m, w, c;
   while(scanf("%ld %ld", &a, &b) == 2){
      if (a < b)
         w = 1;
         w = -1;
      m = 0;
      x = a;
      while (x != b){
         n = x;
         c = 1;
         while (n > 1){
            if (n%2)
               n = n*3 + 1;
               n /= 2;
         if (c > m)
            m = c;
         x +=w;
      printf("%li %li %d\n", a, b, m);
   return 0;
Can anyone help me?

Posted: Wed Feb 08, 2006 4:55 pm
by mamun
You should process all pairs of integers and for each pair determine the maximum cycle length over all integers between and including i and j.

Code: Select all

22 22
21 22

Code: Select all

22 22 16
21 22 16

Posted: Wed Feb 08, 2006 5:20 pm
by f.eliel

thanx man...

Posted: Thu Feb 09, 2006 5:08 am
by tellmewhy
wth???? so i need to write a similar type of class to scanner??? any help ppl?

Posted: Thu Feb 09, 2006 6:14 am
by chunyi81
Have a look the HOWTOs forum. Something there should help.

Posted: Thu Feb 09, 2006 11:34 am
by tellmewhy
ok... i replaced the scanner class using the token..... now got a WA liao.... finally.... :D