CODEWITHSUNDEEP
javalong-integer
Teshtek
Teshtek

Reputation: 1352

Java - Long List ERROR : incompatible types

I'm working on this code, that use big numbers : 

import java.math.*;
import java.util.*;
import java.lang.*;

public class main {
    public static void main(String[] args){
        double max = 1e+15;
        List<Integer> sum = new ArrayList<Integer>();
        sum.add(1);
        long aux = 0;
        for(long i = 1;i<max;i++){
            sum.add(sum.get(i-1)+scomponi(sum.get(i-1),aux));  
            if(i+1==1e+7 || i+1==1e+8 || i+1==1e+9 || i+1 == 1e+10 || i+1 == 1e+10 || i+1==1e+11 || i+1==1e+12 || i+1==1e+13 || i+1==1e+14)
                System.out.println(i+1+"-imo -> "+sum.get(i));  
        }
        System.out.println(sum.get(sum.size()-1)); 
    }    


    public static Long scomponi(Long num,Long tot) {
        while (num > 0) {
            Long digit = num % 10;
            tot += digit;
            num /= 10;
        }
        return tot;
    }
}

But I'm not able to find a solution for this error :

error

What it means? I'm not really good in java, but this is so simple code, what's wrong?

Upvotes: 0

Views: 1069

Answers (2)

AxelH
AxelH

Reputation: 14572

Like janos said, you can't use long index in a List. But from your code, you don't need the list, you only use the last value calculated.

public static void main(String[] args){
    double max = 1e+15;
    long last = 1;
    long aux = 0;
    for(long i = 1;i<max;i++){
        last += scomponi(last,aux);
        if(i+1==1e+7 || i+1==1e+8 || i+1==1e+9 || i+1 == 1e+10 || i+1 == 1e+10 || i+1==1e+11 || i+1==1e+12 || i+1==1e+13 || i+1==1e+14)
            System.out.println(i+1+"-imo -> "+last);
    }
    System.out.println(last);
}

If you really want to keep every values, you could store those into a file but from what I see, you don't need those.

Of couse, the loop will take some time ;)

Upvotes: 1

janos
janos

Reputation: 124804

Lists in Java are int-indexed, as you can see in the javadoc of List.get(), and you're trying to get elements by a long index.

If you need lists bigger than the integer range, you need another data structure that supports that, you cannot use List.

Upvotes: 3

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