Why isn't last condition validated?

Question about the task

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Hey, I can't seem to figure out why the last condition is not validated, I know doing the comparison of i and i+1 doesn't return the right number, but lastly I increase it by 1 and it should get it right. The output is correct for the input given. Thank you!

1. Create a list of numbers.
2. Use the keyboard to add 10 numbers to the list.
3. Display the length of the longest sequence of repeating numbers in the list.

Example for the list 2, 4, 4, 4, 8, 8, 4, 12, 12, 14:
3

The value is 3, because the longest sequence of repeating numbers is three fours.

Requirements:

The program must display a number on the screen.
The program should read values from the keyboard.
In the main method, declare an ArrayList variable with Integer elements and immediately initialize it.
The program should add 10 numbers to the collection in accordance with the conditions.
The program should display the length of the longest sequence of repeating numbers in the list.

package com.codegym.task.task08.task0812; import java.io.*; import java.util.ArrayList; /* Longest sequence */ public class Solution { public static void main(String[] args) throws IOException { //write your code here BufferedReader reader = new BufferedReader(new InputStreamReader(System.in)); ArrayList<Integer> list = new ArrayList<>(); for(int i=0; i<10; i++) { list.add(Integer.parseInt(reader.readLine())); } int maxCount = 0, count = 0; for(int i=0; i<9; i++) { if(list.get(i).equals(list.get(i+1))){ count++; } else { if(count > maxCount) { maxCount = count; } count = 0; } } maxCount++; System.out.println(maxCount); } }

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Misiu

Level 41 , Gdansk, Poland

10 November 2020, 13:10

For all different numbers (no repeating) "count" should be 1. So you should start with count = 1.

raulGLD

Level 8 , Cluj-Napoca, Romania

10 November 2020, 08:45

I've even tried a different approach and still the last one is not passing:

package com.codegym.task.task08.task0812;

import java.io.*;
import java.util.ArrayList;

/*
Longest sequence

*/

public class Solution {
    public static void main(String[] args) throws IOException {
        //write your code here
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));

        ArrayList<Integer> list = new ArrayList<>();
        for(int i=0; i<10; i++) {
            list.add(Integer.parseInt(reader.readLine()));
        }

        int maxCount = 0, count = 0;

        for(int i=0; i<10; i++) {
            for(int j=i+1; j<10-1; j++) {
                if(list.get(i).equals(list.get(j))) {
                    count++;
                } else {
                    if(count > maxCount) {
                        maxCount = count;
                        count = 0;
                    }
                }
            }
        }

        System.out.println(maxCount);


    }
}

Guadalupe Gagnon

Level 37 , Tampa, United States

10 November 2020, 15:00

What misiu said above is correct. Also, this code cuts off a full cycle in the j loop. The list is length ten so the j loop should run as long as j < 10, not j < 9. You should actually consider making both loop run as long as the counter is less than list.size(), then you could pass it a list of any size without having to change the code. Fix those two above. Another issue is that the both count never gets reset and maxValue never gets set unless line 25 is false. Any repeating sequence of numbers at the end of the list, though being counted, would never be considered. Take, for example, this list of ten 1's, which would be a repeating sequence at the end of the list. {1, 1, 1, 1, 1, 1, 1, 1, 1, 1} The correct output for this example would be 10 because there are 10 numbers that repeat in a sequence, however this code (assuming you fixed the first two points at the beginning of this post) would output 0 because line 25 would never be false maxCount is never set. Also, if you output "count" after the two loops, say at line 35, it would output 46 because the count variable is never reset whenever an i loop starts new and just continues incrementing as long as line 25 is true. You can modify this code to account for the bugs mentioned above and pass. Any solve when you are learning is good, however I included a sub-task below if you want an additional challenge. A philosophy in coding is to never do something more that one time. Right now your algorithm reaches line 25 forty six times to compare numbers in a list of 10. If you want a challenge I would recommend trying to structure your code to cut that down to only doing 10 comparisons.