CodeGym/Help with Java Tasks/Code runs correctly, test fails

Level 8

25.12.2018
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Code runs correctly, test fails

Question about the task

Under discussion

package com.codegym.task.task07.task0712;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;

/*
Shortest or longest

*/

public class Solution {
    public static void main(String[] args) throws Exception {
        //write your code here
        ArrayList<String> listString = new ArrayList<>();
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
        for (int i = 0; i < 10; i++) {
            listString.add(reader.readLine());
        }
        int shortest = listString.get(0).length();
        int postitionShort = 0;
        int positionLong = 0;
        boolean firstShort = false;
        boolean firstLong = false;
        boolean found = false;
        int longest = listString.get(listString.size() - 1).length();

        for (int i = 0; i < listString.size(); i++) {
            if (shortest > listString.get(i).length()) {
                shortest = listString.get(i).length();
                postitionShort = i;
            }
            if (longest < listString.get(i).length()) {
                longest = listString.get(i).length();
                positionLong = i;
            }
        }
        for (int i = 0; i < listString.size(); i++) {
            if (i == positionLong) {
                firstLong = true;
                System.out.println(listString.get(i));
                break;
            } else if (i == postitionShort) {
                firstShort = true;
                System.out.println(listString.get(i));
                break;

            }
        }

    }
}

1. Create a list of strings.
2. Add 10 strings from the keyboard.
3. Find out which string occurs earlier in the list: the shortest or the longest.
If several strings are shortest or longest, then consider the very first such string encountered.
4. Display the string described in Step 3. One string should be displayed.

Requirements:

Declare a string list variable and immediately initialize it.
The program should read 10 strings from the keyboard and add them to the list.
The program should display the shortest string if it comes before the longest.
The program should display the longest string if it comes before the shortest.

package com.codegym.task.task07.task0712; import java.io.BufferedReader; import java.io.IOException; import java.io.InputStreamReader; import java.util.ArrayList; /* Shortest or longest */ public class Solution { public static void main(String[] args) throws Exception { //write your code here ArrayList<String> listString = new ArrayList<>(); BufferedReader reader = new BufferedReader(new InputStreamReader(System.in)); for (int i = 0; i < 10; i++) { listString.add(reader.readLine()); } int shortest = listString.get(0).length(); int postitionShort = 0; int positionLong = 0; boolean firstShort = false; boolean firstLong = false; boolean found = false; int longest = listString.get(listString.size() - 1).length(); for (int i = 0; i < listString.size(); i++) { if (shortest > listString.get(i).length()) { shortest = listString.get(i).length(); postitionShort = i; } if (longest < listString.get(i).length()) { longest = listString.get(i).length(); positionLong = i; } } for (int i = 0; i < listString.size(); i++) { if (found == false) { if (i == positionLong) { found = true; System.out.println(listString.get(i)); } else if (i == postitionShort) { found = true; System.out.println(listString.get(i)); } } } } }

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Hashirama

Level 26 , Port-Harcourt, Nigeria

16 January 2019, 15:29

How about you do it my way: simple and effortless. Get two strings, call them longest and shortest and asign the first string on the list array to them. Get two int variables; call them max and min and assign 0 to them. Use a loop and test if the shortest string is actually the shortest in the list array. If it isn't, then assign the shortest to it and also assign the very index number where you got the shortest to min. Do the same for the longest After that. Test between the min and max. If min is lesser, then print the string at index min from the array list else print the string at index max If want me to attach the code just Holla!!

Guadalupe Gagnon

Level 37 , Tampa, United States

26 December 2018, 02:34

You are doing a lot of things. What you want to do is keep things easy. Break it down into manageable parts and add notes of what you want to do as an outline before you start writing code. Also, i would use an array instead of arraylist because you know the size. Here is an example outline which you are more than welcome to use:

//step 1: create array/list and fill with values (completed in lines 16-20)

//step 2: create a copy of the string values array/list

//step 3: sort copy by length.

//step 3 and 4: pull the first value and last value from copy and get their length.
//Set them to max and min values of length

//step 5: iterate through original array/list and return the first value that length
//equals min OR max

google help with each step if you cant figure it out, or just want a fast way of doing it. I use stackoverflow.com all the time to copy/paste code into my solutions. Coding is all about using what people before you have already solved.

Guadalupe Gagnon

Level 37 , Tampa, United States

26 December 2018, 03:00

Your code ran in 0 milliseconds, while mine (following the pattern i gave) ran in 3 ms, however yours is outputting the wrong value. I fed both programs string values as such: {"several", "strings", "are", "shortest","or", "longest", "then", "consider", "the", "very", "first", "such", "string", "encountered"} The correct output should be "or", but yours output "several".

hidden #10412202

Level 8

26 December 2018, 06:07

You are wrong. 1. the input of my code takes only 10 words as asked, you supply 14 words 2. when running my program it correctly returns' shortest', which is before 'or' and gives me the longest one before the shortest one Thank you for taking the time to evaluate, but again, my code gives the correct output but the test is failing.

Guadalupe Gagnon

Level 37 , Tampa, United States

26 December 2018, 14:24

Hello, I hard code in values to test code, i can hard code any amount in and the code should still work the same, whether 14 or 14 million. The requirements say that "If several strings are shortest or longest, then consider the very first such string encountered." In my list the shortest word is 'or', and the longest word is 'encountered'. Because 'or' is entered before 'encountered', the correct output is or. Instead of arguing, here is the correct solution, hopefully next time we encounter you will heed my advice more carefully:

public class Solution {
    public static void main(String[] args) throws Exception {
        //step 1: create array/list and fill with values (completed in lines 16-20)
        BufferedReader r = new BufferedReader(new InputStreamReader(System.in));
        String[] strings = new String[10];
        for(int i = 0; i < strings.length; i++)  strings[i] =r.readLine();

        //step 2: create a copy of the string values array/list
        String[] copy = Arrays.copyOf(strings, strings.length);

        //step 3: sort copy by length.
        Arrays.sort(copy, new java.util.Comparator<String>() {
            public int compare(String s1, String s2) {
                return s1.length() - s2.length();// comparision
            }
        });
        //step 3 and 4: pull the first value and last value from copy and get their length.
        //Set them to max and min values of length
        int min = copy[0].length();
        int max = copy[copy.length-1].length();


        //step 5: iterate through original array/list and return the first value that length
        //equals min OR max
        for(String s:strings){
            if(s.length() == min || s.length() == max) {
                System.out.println(s);
                break;
            }

        }
    }
}

hidden #10412202

Level 8

26 December 2018, 18:11

Thank you for your reply, Again, you are completely wrong, the requirements say: 2. Add 10 strings from the keyboard. Where did you come up with 14 or 14 million? It says 10 strings. TEN not 14, not 14 million. If it would be 14 as input or 14 million my code would still work. If you enter the 10 words from your sentence it shows the correct output. Yours is not validating at all. I want to help you since you have a problem grasping some simple concepts and reading legacy code (mine in this case). My code is working but not passing the test on the site. Don't know what you are trying to prove to me, your code is not passing either.

Guadalupe Gagnon

Level 37 , Tampa, United States

26 December 2018, 18:35

I've run your code and it outputs the wrong value, my code outputs the right value. It doesn't let me verify as I have already completed the task. I missed the requirement that you had to initialize an array list: change line 5 to:

ArrayList<String> strings = new ArrayList<>();

and line 22 to:

String[] copy = strings.toArray(new String[0]);

and validation will pass

Guadalupe Gagnon

Level 37 , Tampa, United States

26 December 2018, 18:44

See Below:

public static void main(String[] args) throws Exception {
        //write your code here
        String[] strings = {"several", "strings", "are", "shortest","or", "longest", "then", "consider", "the", "very", "first", "such", "string", "encountered"};
        ArrayList<String> listString = new ArrayList<>();
        //BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
        for (int i = 0; i < strings.length; i++) { // change back to 10 instead of strings.length
            //listString.add(reader.readLine());
            listString.add(strings[i]);
        }
        int shortest = listString.get(0).length();
        int postitionShort = 0;
        int positionLong = 0;
        boolean firstShort = false;
        boolean firstLong = false;
        boolean found = false;
        int longest = listString.get(listString.size() - 1).length();

        for (int i = 0; i < listString.size(); i++) {
            if (shortest > listString.get(i).length()) {
                shortest = listString.get(i).length();
                postitionShort = i;
            }
            if (longest < listString.get(i).length()) {
                longest = listString.get(i).length();
                positionLong = i;
            }
        }
        for (int i = 0; i < listString.size(); i++) {
            if (found == false) {
                if (i == positionLong) {
                    found = true;
                    System.out.println(listString.get(i));
                } else if (i == postitionShort) {
                    found = true;
                    System.out.println(listString.get(i));

                }
            }
        }

    }

Guadalupe Gagnon

Level 37 , Tampa, United States

26 December 2018, 18:52

It is very easy to modify code for testing. The reason I supply the string values (i used 14 [but could use 14 million or 10]) is because entering values each and every time you want to test it is very time consuming. I added line 8 and 13 and commented out your lines that read user input. Now it is using the values i supplied. It outputs "several" where it should output "or". You can test your code using this method and change the values in strings to anything you want. When it works properly delete the new lines of code and un-comment the original ones. I am just trying to help you. Here is another way to provide strings instead of entering them by each value: Copy a string, paste it in, and call split(" ") on it. This returns an array such as:

String[] strings = "is because entering values".split(" ");

now strings stores the words "is", "because", "entering", "values".

Guadalupe Gagnon

Level 37 , Tampa, United States

26 December 2018, 19:10

Your bug is on line 27. it should be:

int longest = Integer.MIN_VALUE;

whenever the longest word entered is the last word, the int positionLong is never changed from 0. That means that when the last word entered is the longest your code will always return the first word entered. This is why you are failing. You could probably change line 10 to Integer.MAX_VALUE, but because you pulled the first word, if it never changes it would still be correct.