100 - The 3n + 1 problem

[ergysr]

Hi all,
i just registered and made my first submission(3n+1) on the online judge, but i got WA. I'm quite sure my algorithm is correct, but i think my problem is input & output. Should i input values via input file(what' the name of that file) or values are entered manually? What about the output? A file or just a writeln function? Somebody clarify me please...

[Darko]

You read input from standard in and write to standard out.

[ergysr]

You read input from standard in and write to standard out.

Thnx darko, read all test cases and then output results? or just input output, input output?

[Darko]

You can output result of each test case after you process it. Or you can do it all at once. It doesn't really matter, what they do is redirect your output to a file and then compare with their results (or run a program to check it).

I am guessing you are using Pascal, so I can't really help you much, but they posted a solution to 100, maybe that can help:
http://online-judge.uva.es/problemset/data/p100.p.html

[ergysr]

You can output result of each test case after you process it. Or you can do it all at once. It doesn't really matter, what they do is redirect your output to a file and then compare with their results (or run a program to check it).

I am guessing you are using Pascal, so I can't really help you much, but they posted a solution to 100, maybe that can help:
http://online-judge.uva.es/problemset/data/p100.p.html

thanks darko, really thanks.

[Hatty]

Getting wrong answer, I dont know why...

Edit: Code removed. Thanks sapnil, didnt have to use long int though, as the challenge says that all numbers are below 1mil

It works, but I don't know why I get wrong answer...

Code: Select all

hatty@study:~/dev/uva$ ./100
1 10
1 10 20
100 200
100 200 125
201 210
201 210 89
900 1000
900 1000 174

hatty@study:~/dev/uva$ 

Those are the same inputs and outputs as in the problem.. Help?

[sumonSUST]

I get TLE plz help me

Code: Select all

//Removed

Thanks
sumon

[sapnil]

To sumon

Just change this line:

Code: Select all

while(n!=1)
to
while(n>1)

Thanks
Keep posting
Sapnil

[sumonSUST]

To sapnil

Thanks.
I get ACC now

Sumon

[sapnil]

To Hatty

Your problem is in taking input.
Make it simple

Code: Select all

while(scanf("%ld %ld",&j,&i)==2)
{

}

>> use long data type
>> remove your code after Acc

Thanks
Keep postingh
sapnil

[think12381]

Dear all
I test some numbers to my code but no error can't be finded!!
Send this code to Online Judge, it always tells me "WA".
May you tell me what WA is happened on my code ???

Thank you!


#include <stdio.h>

long algorithm(long );
void swap(long *,long*);

int main(int argc, char *argv)
{
long i,j,first=0,second=0,temp=0,n=0;

while(scanf("%ld%ld",&i,&j)==2)
{
if((i<=0) || (j<=0) || (i>1000000) || (j>1000000))
{
printf("the two number is error!!\n");
exit(1);
}

if((i==1) && (j==1))
{
temp=1;
}
else
{
if(j<i)
swap(&i,&j);

temp = algorithm(i);
i=i+1;
for(i;i<j;i++)
{

second=algorithm(i);

if(temp<second)
temp=second;
}
}
printf("MAX cycle length is =%d\n",temp);
}

return 0;
}

long algorithm(long n)
{
int time=1;

do
{
if((n%2)==0)
{
n=n/2;
}
else
{
n=n*3+1;
}
time++;
}while(n!=1);

return time;
}

void swap(long *i,long*j)
{
long c;

c=*j;
*j=*i;
*i=c;
}

[mf]

You should strictly follow the sample output, as described in the section "The Output" of the problem statement. Essentially, output of your program is compared with a correct output file, and if any single byte doesn't match you get WA.

Printing anything extra, like the message "MAX cycle length is " will definitely result in WA, even if numbers are OK.

[ithenewguyi]

can anyone explain how does the java input provided works?
why cant we use Scanner? for some problems, how do we tell if the input is over? do we use Scanner.hasNext() method?
thanks for any "input"

[mf]

You can use Scanner.

[ithenewguyi]

thanks for the reply, and so we could use .hasNext() method to check if the input is finished?

I'm not sure why i get a WA then
for the problem 100, i took care of the i>j or i<j and still...

Code: Select all

/* problem 100
 * 3n + 1 problem
 */
import java.util.*;
class Main
{
  public static void main(String[] args)
  {
    Scanner in = new Scanner (System.in);
    try {
      while (in.hasNext()){
        String numbers = in.nextLine();
        String[] num = numbers.split(" ");
        
        long num1 = Long.parseLong(num[0]);
        long num2 = Long.parseLong(num[1]);
        
        long big;
        long small;
        if (num1 > num2){
          big = num1;
          small = num2;
        }
        else {
          big = num2;
          small = num1;
        }
        long temp;
        long counter=1;
        long biggest=1;
        for (long i = small; small <= big; small++)
        {
          temp = small;
          while (temp != 1){
            if (temp % 2 == 0){
              temp /= 2;
              counter++;
            }
            else{
              counter++;
              temp = temp * 3 +1;
            }
          }
          if (counter>biggest)
            biggest=counter;
          counter=1;
        }
        System.out.println(numbers+" "+biggest);
      }
    }catch (Exception e){System.exit(0);}
  }
}