243. Shortest Word Distance

Problem:

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.

Analysis:

找到两个单词尽可能近的距离。比如2个单词位置顺序为 

位置：  1,2,1,2,2

index:   0,2,4,5,7  

肯定是0和2先比较。 走到4,word1又出现了一次，和2比较。走到5，word2出现第二次和4比较。

Solution:

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