[LeetCode] Shortest Word Distance

Problem Description:

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.

Note:
You may assume that word1 does not equal to word2, and word1 and word2 are both in the list.

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The naive idea is very easy. But could you solve it in one-pass? Well, the one-pass code (taken from here) is rewritten in C++ as follows.

class Solution {
public:
    int shortestDistance(vector<string>& words, string word1, string word2) {
        int n = words.size(), idx1 = -1, idx2 = -1, dist = INT_MAX;
        for (int i = 0; i < n; i++) {
            if (words[i] == word1) idx1 = i;
            else if (words[i] == word2) idx2 = i;
            if (idx1 != -1 && idx2 != -1)
                dist = min(dist, abs(idx1 - idx2));
        }
        return dist;
    }
};