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