100 - The 3n + 1 problem

[brianfry713]

Don't read from a file. You can see a sample solution to problem 100 at:
http://uva.onlinejudge.org/index.php?op ... &Itemid=30

[hercules]

Thanks for your advice

[magnetik]

My answer to problem 100 is pasted here on ideaone.

As you can see from the input and output, the program works as expected.

However, using the online judge I get "runtime error."

What is the problem?

Edit:

Ok, based on reading some previous posts I have made my program handle reversed ranges.

Updated code is here http://ideone.com/HK0ugg

However, I still get "runtime error." What is the problem?

[magnetik]

Nevermind, I simply wasn't returning 0. It works

[Fedaykin]

Code: Select all

import java.util.*;

class Main {

	public static void main(String[] args){
		new Main().solveProblem();
	}

	public void solveProblem(){
		final Scanner in = new Scanner(System.in);
		while(in.hasNextInt()){
			int i = in.nextInt();
			int j = in.nextInt();
			int[] values = new int[j-i+1];
			for(int k = i;k <= j;k++){
				values[k-i] = findSeqNum(k);
			}
			int most = getMax(values,j-i+1);
			System.out.println(""+i+" "+j+" "+most);
		}
		in.close();
	}

	public int findSeqNum(int n){
		int count = 1;
		while(n != 1){
			if(n%2 == 0)
				n = n / 2;
			else
				n = 3 * n + 1;
			count++;
		}
		return count;
	}

	public int getMax(int[] vals,int size){
		int max = vals[0];
		for(int i = 0;i < size;i++)
			if(vals[i] > max)
				max = vals[i];
		return max;
	}
}

So what am I doing wrong here?

[brianfry713]

What happens if i>j?

[Tiny]

Hello i am new to the UVA online Judge.
I copied the sample program that is a solution to problem 100.
But I get a compilation error ewvery time i submit that program.

This is the sample i try to get AC i found it on the site of UVA
What can be wrong?

program p100 ;
var
i, j: integer;
function getCL(N: integer): integer;
var k: integer;
begin
k := 1;
while N <> 1 do begin
if odd(N) then N := 3*N + 1
else N := N div 2;
k := k + 1;
end;
getCL := k;
end;
function getMaxCL(i, j: integer): integer;
var k: integer;
max, curCL: integer;
begin
max := 0;
for k:=i to j do begin
curCL := getCL(k);
if curCL > max then max := curCL;
end;
getMaxCL := max;
end;
begin
{$IFNDEF ONLINE_JUDGE}
assign(input, 'input.txt');
reset(input);
assign(output, 'output.txt');
rewrite(output);
{$ENDIF}
while not eof(input) do begin
readln(i, j);
write(i, ' ', j, ' ');
if i < j then
writeln(getMaxCL(i, j))
else
writeln(getMaxCL(j, i));
end;
{$IFNDEF ONLINE_JUDGE}
close(input);
close(output);
{$ENDIF}
end.

[Tiny]

Can anyone post a program for problem 100 then got AC.
I tried the sample program but than got TLE and RTE.
I like to know what I'm doing wrong in my submissions.

Thanks

[farnaws123]

Code: Select all

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
package sample_java;

/**
 *
 * @author Nawshad
 * Problem: 100
 */
// 

import java.io.IOException;
import java.util.StringTokenizer;

class Main
{
    static String ReadLn (int maxLg)  // utility function to read from stdin
    {
        byte lin[] = new byte [maxLg];
        int lg = 0, car = -1;
        String line = "";

        try
        {
            while (lg < maxLg)
            {
                car = System.in.read();
                if ((car < 0) || (car == '\n')) break;
                lin [lg++] += car;
                
            }
        }
        catch (IOException e)
        {
            return (null);
        }

        if ((car < 0) && (lg == 0)) return (null);  // eof
        return (new String(lin, 0, lg));
    }

    int loop(int i)
    {
        int n=i;
        int count=1;
        while(n>1)
        {
            if(n%2==0)
            {
                n=n/2;
            }
            else
            {
                n=3*n+1;
            }
            count++;
        }
       return count; 
    }

    int max_cycle(int j,int k)
    {

        int max=-1;
        for(int i=j;i<k;i++)
        {
            int count=loop(i);
            if(count>max)
            {
                max=count;
            }
        }
        return max;
    }

    
    
    public static void main (String args[])  // entry point from OS
    {
        Main myWork = new Main();  // create a dinamic instance
        myWork.Begin();            // the true entry point
    }

    void Begin()
    {
        String input;
        StringTokenizer idata;
        int a, b, min, max;

        while ((input = Main.ReadLn (255)) != null)
        {
          idata = new StringTokenizer (input);
          a = Integer.parseInt (idata.nextToken());
          b = Integer.parseInt (idata.nextToken());
          if (a < b) { min=a; max=b; } else { min=b; max=a; }
       
         System.out.println (a + " " + b + " " + max_cycle(min, max));
        }
          
    }
    
    
}

What could be the possible reason for RE for that code?

[brianfry713]

Don't use a package
http://uva.onlinejudge.org/index.php?op ... &Itemid=30

[farnaws123]

now getting WA..:/

[brianfry713]

Input:

Code: Select all

1 1

AC output:

Code: Select all

1 1 1

[RoniphpBB]

AC

[brianfry713]

There is more than one case in the sample input and output. You should continue reading i and j until there are no more. Do a loop like:
while(cin >> i >> j) {
...
}

[sasy222]

Hi everybody,

I was trying to solve 3n+1 exercise . I don't know how to get input.
can anybody help?