[Lintcode easy]Longest Words

Longest Words

Given a dictionary, find all of the longest words in the dictionary.

 

Example

Given

{
  "dog",
  "google",
  "facebook",
  "internationalization",
  "blabla"
}

the longest words are(is) ["internationalization"].

Given

{
  "like",
  "love",
  "hate",
  "yes"
}

the longest words are ["like", "love", "hate"].

Challenge

It's easy to solve it in two passes, can you do it in one pass?

 

////First，tracking the array to record every word's length, and find out the max length

////the second loop is to find out specific words.

/// keep in mind how to initiate the int array.

class Solution {
    /**
     * @param dictionary: an array of strings
     * @return: an arraylist of strings
     */
    ArrayList<String> longestWords(String[] dictionary) {
        // write your code here
   
        ArrayList<String> newString=new ArrayList<String>();
        
        int count[]=null;
        int m=dictionary.length;
        count=new int[m];
        int max=0;

        
        for(int i=0;i<dictionary.length;i++)
        {

            int n=dictionary[i].length();
            count[i]=n;
            max=Math.max(n,max);
        }
        
        for(int i=0;i<dictionary.length;i++)
        {
            if(count[i]==max)
            {
                newString.add(dictionary[i]);
            }
        }
        
        return newString;
       
    }

 

if we use hashtable, we can do it in one pass

following is the code,

using the word's length as key, words as value,

when it is the same key, add another words to hashmap.

find the max key, return its value.

class Solution {
    /**
     * @param dictionary: an array of strings
     * @return: an arraylist of strings
     */
    ArrayList<String> longestWords(String[] dictionary) {
        // write your code here

        HashMap<Integer,ArrayList<String>> map=new HashMap<Integer,ArrayList<String>>();
    
        int max=0;
        
        for(int i=0;i<dictionary.length;i++)
        {
           if(map.containsKey(dictionary[i].length()))
           {
                map.get(dictionary[i].length()).add(dictionary[i]);
           }
            else
           {
               ArrayList<String> arr=new ArrayList<String>();
               arr.add(dictionary[i]);
               map.put(dictionary[i].length(),arr);
           }
            max=Math.max(dictionary[i].length(),max);
        }
        return map.get(max);
    }
};