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.

思路1：用idx1 来记录上次word1出现的index，idx2来记录上次word2出现的index，这样每次跟新index1，index2的时候都减去上次出现的值，因为扫描是从左往右一直扫描。那么这样每次更新就会得到最小值。 O(n).

public class Solution {
    public int shortestDistance(String[] words, String word1, String word2) {
        if(words == null || words.length == 0 || word1 == null || word2 == null) return 0;
        int index1 = -1; 
        int index2 = -1;
        int mindis = Integer.MAX_VALUE;
        for(int i=0; i<words.length; i++){
            if(words[i].equals(word1)){
                index1 = i;
                if(index2 != -1){
                    mindis = Math.min(mindis, index1 - index2);
                }
            }
            if(words[i].equals(word2)){
                index2 = i;
                if(index1 != -1){
                    mindis = Math.min(mindis, index2 - index1);
                }
            }
        }
        return mindis;
    }
}