Shortest Word Distance

Given a list of words and two words word1 and word2, return the shortest distance between these two words in the list.

For example,
Assume that words = ["practice", "makes", "perfect", "coding", "makes"].

Given word1 = “coding”, word2 = “practice”, return 3.
Given word1 = "makes", word2 = "coding", return 1.

Note:
You may assume that word1 does not equal to word2, and word1 and word2 are both in the list.

解法一：

public class Solution {
    public int shortestDistance(String[] words, String word1, String word2) 
    { 
        int idx1=-1;
        int idx2=-1;
        int min=Integer.MAX_VALUE;
        for(int i=0;i<words.length;i++)
        {
            if(words[i].equals(word1))
            {
                idx1=i;
                if(idx2!=-1)min=Math.min(min,idx1-idx2);
            }
            if(words[i].equals(word2))
            {
                idx2=i;
                if(idx1!=-1)min=Math.min(min,idx2-idx1);
            }
            
        }
        return min;
        
    }
}

解法二：

hashtable

public class Solution {
    public int shortestDistance(String[] words, String word1, String word2) 
    {
        HashMap<String, ArrayList<Integer>> map = new HashMap<String,ArrayList<Integer>>();
        for(int i=0;i<words.length;i++)
        {
            String word = words[i];
            if(!map.containsKey(word))
            {
                map.put(word,new ArrayList<Integer>());
            }
            map.get(word).add(i);
        }
        
        ArrayList<Integer> list1 = map.get(word1);
        ArrayList<Integer> list2 = map.get(word2);
        int i = 0;
        int j = 0;
        int min = words.length-1;
        while(i<list1.size()&&j<list2.size())
        {
            int index1 = list1.get(i);
            int index2 = list2.get(j);
            
                min = Math.min(Math.abs(index1-index2),min);
                if(index1<index2)
                {
                    i++;
                    
                }
                else
                {
                    j++;
                }
            
        }
        return min;
    }
}