The programm seems works correct, but don't pass third condition

Question about the task

Identical words in a list

Java Syntax, Level 10, Lesson 11

Resolved

Read a list of 20 words from the keyboard.
You need to count how many times each word appears in the list.
The result should be represented as a Map<String, Integer>, where the key is a unique word, and the value is the number of times the word appears in the list.

Display the contents of the map.
The case (uppercase/lowercase) affects the results.

Requirements:

The countWords method must declare and initialize a HashMap<String, Integer>.
The countWords method must return the created map.
The countWords method should add keys that correspond to unique words, and values that correspond to how many times those words occur.
The program should display the resulting map.
The main method must call the countWords method.

package com.codegym.task.task10.task1016; import java.io.BufferedReader; import java.io.InputStreamReader; import java.util.ArrayList; import java.util.HashMap; import java.util.Map; import java.util.*; /* Identical words in a list */ public class Solution { public static void main(String[] args) throws Exception { BufferedReader reader = new BufferedReader(new InputStreamReader(System.in)); ArrayList<String> words = new ArrayList<String>(); for (int i = 0; i < 20; i++) { words.add(reader.readLine()); } Map<String, Integer> map = countWords(words); for (Map.Entry<String, Integer> pair : map.entrySet()) { System.out.println(pair.getKey() + " " + pair.getValue()); } } public static Map<String, Integer> countWords(ArrayList<String> list) { HashMap<String, Integer> result = new HashMap<String, Integer>(); //write your code here for(int n = 0; n < list.size(); n++) { int count = 0; String str = list.get(n); Iterator<String> it = list.iterator(); while(it.hasNext()) { if(str.equals(it.next())){ count++; it.remove(); } } result.put(str, count); } return result; } }

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Guadalupe Gagnon

Level 37 , Tampa, United States

18 April 2019, 13:27

useful

The countwords method is flawed. The loop starts by grabbing the next word in line from list, then it counts how many times that word appears in the list. The problem is that the words at each index get moved around when you remove items. For example: the first loop cycle, where n = 0, the first word is removed (the one at index 0), the second word in the list is moved down to replace it (at index 0), the code continues until all the current words are counted, then the for loop moves to n = 1 and the code pulls the word at index 1. This effectively skips the word that is currently at index 0. This needs to be fixed.

SilverZax

Level 18 , Poltava, Ukraine

22 April 2019, 11:24

solution

Thanks for your help. This is how i fix it.

public static Map<String, Integer> countWords(ArrayList<String> list) {
       HashMap<String, Integer> result = new HashMap<String, Integer>();

       //write your code here
       for(int n = 0; n < list.size(); n++) {
           int count = 0;
           String str = list.get(n);
           Iterator<String> it = list.iterator();
           while(it.hasNext()) {
               if(str.equals(it.next())){
                   count++;
               }
           }
           if(!result.containsKey(str))
               result.put(str, count);
       }


       return result;