243. Shortest Word Distance

// LeetCode URL: https://leetcode.com/problems/shortest-word-distance/

/**
 * Compare each word with word1 and word2 and store the minimum distance seen
 * till now.
 *
 * Time Complexity: O(L * N)
 *
 * Space Complexity: O(1)
 *
 * N = Number of words in words array. L = Average length of a word in words
 * array.
 */
class Solution {
    public int shortestDistance(String[] words, String word1, String word2) {
        if (words == null || words.length == 0 || word1 == null || word2 == null) {
            return -1;
        }

        int result = Integer.MAX_VALUE;
        int index1 = -1;
        int index2 = -1;

        for (int i = 0; i < words.length; i++) {
            if (words[i].equals(word1)) {
                index1 = i;
            }
            if (words[i].equals(word2)) {
                index2 = i;
            }
            if (index1 != -1 && index2 != -1) {
                result = Math.min(result, Math.abs(index1 - index2));
            }
        }

        return result == Integer.MAX_VALUE ? -1 : result;
    }
}