Leetcode 243 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.

Solution 1: simple iterate the array and keep track last different word appearance.

 public class Solution {  
   public int shortestDistance(String[] words, String word1, String word2) {  
     int res=Integer.MAX_VALUE;  
     int n=words.length;  
       int pre1=-1, pre2=-1;  
       for (int i=0; i<n; i++) {  
         if (words[i].equals(word1)) pre1=i;  
         else if (words[i].equals(word2)) pre2=i;  
         else continue;  
         if (pre1>0 && pre2>0) res=Math.min(res,Math.abs(pre1-pre2));  
       }   
       return res;  
   }  
 }