LC 245. Shortest Word Distance III 【lock, medium】

Given a list of words and two words word1 and word2, return the shortest distance between these two words in the list.

word1 and word2 may be the same and they represent two individual words in the list.

Example:
Assume that words = ["practice", "makes", "perfect", "coding", "makes"].

Input: word1 = “makes”, word2 = “coding”
Output: 1

Input: word1 = "makes", word2 = "makes"
Output: 3

Note:
You may assume word1 and word2 are both in the list.

这题虽然可以沿用上一题的思路，但是可以有更简单的两个index的做法，最优解O(n)，runtime 8ms。

class Solution {
public:
    int shortestWordDistance(vector<string>& words, string word1, string word2) {
        int index = -1;
        int minval = words.size();
        for(int i=0; i<words.size(); i++){
            if((index != -1) && (words[i] == word1 || words[i] == word2)){
                if((words[index] == word1 && words[i] == word2) || 
                   (words[index] == word2 && words[i] == word1)){
                    minval = min(minval, i - index);
                }
            }
            if(words[i] == word1 || words[i] == word2)
                index = i;
        }
        return minval;
    }
};