244.最短单词距离II

方法：哈希表+双指针

class WordDistance {
    HashMap<String,List<Integer>> map = new HashMap<>();

    public WordDistance(String[] wordsDict) {
        int len = wordsDict.length;
        for(int i =0;i< len;i++){
            String word = wordsDict[i];
            if(!map.containsKey(word)){
                map.put(word,new ArrayList<>());
            }
            map.get(word).add(i);
        }
    }
    
    public int shortest(String word1, String word2) {
        List<Integer> map1 = map.get(word1);
        List<Integer> map2 = map.get(word2);
        int size1 = map1.size(),size2 = map2.size();
        int pos1 = 0,pos2 = 0;
        int ans = Integer.MAX_VALUE;
        while(pos1 < size1 && pos2 < size2){
            int index1 = map1.get(pos1),index2 = map2.get(pos2);
            ans = Math.min(ans,Math.abs(index1-index2));
            if(index1 < index2){
                pos1++;
            }else{
                pos2++;
            }
        }
        return ans;
    }
}

/**
 * Your WordDistance object will be instantiated and called as such:
 * WordDistance obj = new WordDistance(wordsDict);
 * int param_1 = obj.shortest(word1,word2);
 */