100 - The 3n + 1 problem

[amzad.ethan]

Here is my code. can anyone tell me why I have got WA???

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import java.util.Scanner;
class Main
{
  public static void main(String [] args)
  {
    Scanner e=new Scanner(System.in);
    while (e.hasNext())
    {
      int p=0;
      int r=0;
      int i= e.nextInt();
      int j = e.nextInt();
      if (j<i)
      {
        p=i;
        r=j;
        int temp=i;
        i=j;
        j=temp;
      }
      else 
      {
        p=i;
        r=j;
      }
      int [] a=new int [j+1];
      int m=i;
      while (m<=j)
      {
        int n=m;
        int c=1;
        while (n!=1)
        {
          if (n%2!=0)
          {
            n=3*n+1;
          }
          else 
          {
            n=n/2;
          }
          c++;
        }
        a[m]=c;
        m++;                  
      }
      int max=a[0];
      int c=1;
      while (c<j)
      {
        if (max<a[c])
        {
          max=a[c];
        }
        c++;
      }
      System.out.println(p+" "+r+" "+max);
    }
  }
}

[brianfry713]

Input:

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1 1
1 2
2 2

Correct output:

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1 1 1
1 2 2
2 2 2

[gautamsingh]

I submitted this code about 20 minutes ago and still no verdict is being shown. Submission ID is 13533745 and same for 13533473 which was submitted about an hour ago. (this one's incorrect though)

Code: Select all

#include <algorithm>
#include <cstdio>
#define INF 9999999
using namespace std;
int a[1000050];
int coll(int p)
{
	int c = 1, temp = p;
	if (a[p] != 0)
		return a[p];
	else
	{
		while (temp != 1)
		{
			if (temp % 2 == 0)
				temp /= 2;
			else
				temp = 3*temp + 1;
			++c;	
		}
		a[p] = c;
	}
	return c;
}	
int main() 
{
	int i, j;
	while ((scanf ("%d%d", &i, &j)) != EOF)
	{
		int ans = -INF;
		for (int p = min(i, j); p <= max(i, j); ++p)
			ans = max(ans, coll(p));
		printf ("%d %d %d\n", i, j, ans);	
	}
	return 0;
}

[brianfry713]

The judge is currently having issues, try again later.

[gautamsingh]

The judge is currently having issues, try again later.

I got it accepted. The judge was too slow. Thanks for your help. Should I delete the code posted above?

[samoel_stt]

I keep getting wrong answer, what i am doing wrong?

Code: Select all

#include <stdio.h>
#include <stdlib.h>
int proceso(long num){
    int cont = 1;
    while( num != 1){
        if (num % 2 == 1) num = 3*num+1;
        else num = num/2;
        cont++;
    }   
    return cont;
}
void ciclo3n(int n1,int n2, int *max){
    int i;
    int maximo = proceso(n1);
    for(i=n1+1;i<=n2;i++){
        int cur = proceso(i);
        if(cur > maximo)
            maximo = cur;        
    }
    *max = maximo;
}
int main(int argc, char** argv) {
    long n1=0,n2=0;
    for(;;){
        if ( scanf("%d %d",&n1,&n2) == EOF) break;
        if (0<n1 && n1<1000000 && 0<n2 && n2<1000000){
            if (n1 > n2){
                int aux = n1;
                n1 = n2;
                n2 = aux;
            }
            int max=0;
            ciclo3n(n1,n2,&max);
            printf("%d %d %d\n",n1,n2,max);
        }        
    }
    return 0;
}

[Shadow_Coder]

Given below is my code. It works for all the test cases which I've tried, it swaps i and j, if i>j as well. Yet, it's still getting WA. Any suggestions?

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#include <iostream>
#include <algorithm>
using namespace std;

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

int main() {
    int i, j, I, J, Max;
    while(!cin.eof()){
    	cin >> i >> j;
    	cout << i << " " << j << " "; 
    	I = min(i, j); J = max(i, j);
    	Max = -1;
    	for(int k=I;k<=J;k++){
    		Max = max(Max, cycleLength(k)); 
    	}
    	cout << Max;
    	if(!cin.eof()) { cout << "\n"; }
    }
	return 0;
}

[brianfry713]

Input:

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9 1

AC output:

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9 1 20

[brianfry713]

Change your loop to while(cin >> i >> j) {
Don't use cin.eof() while reading integers because the last line of the input will end with a newline char.
Also make sure you always print a newline char at the end of the last line.

[Shadow_Coder]

I got AC, but tell me, why do we need a newline character at the end of the last line, when it is not so in the sample output?

[villainoftime]

Why am I getting wrong answer, please??

#include<stdio.h>


int collatz(int n);
int cyclecounter(int n);

int main()
{
int i, j, cycle, MAX;
while(scanf("%d %d", &i, &j)==2)
{
MAX=0;
int n=i, p;
if(i>j)
p=-1;
else
p=1;
for(; n!=j; n+=p)
{
int cycle=cyclecounter(n);
if(MAX<cycle)
MAX=cycle;
}
printf("%d %d %d\n", i, j, MAX);
}
return 0;
}




int collatz(int n)
{
if(n%2==0)
return(n/2);
return(3*n+1);
}


int cyclecounter(int n)
{
int cycle=0;
n=collatz(n);
cycle++;
while(n!=1)
{
n=collatz(n);
cycle++;
}
return(cycle+1);
}

[brianfry713]

If you want to get AC, always print a newline char at the end of the last line.

[brianfry713]

Input 1 1, output should be 1 1 1

[sampad74]

Got AC

[brianfry713]

i or j might be larger than 10000