leetcode解题: Shortest Word Distance (243)

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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.

解法1：

思路就是维护两个指针，一个记录上一次出现的word1的位置，另一个记录word2的位置。每次发现一个新位置的时候计算一下当前的距离并且更新最短距离。
C++

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class Solution {
public:
    int shortestDistance(vector<string>& words, string word1, string word2) {
        int iter1 = -1, iter2 = -1;
        int res = words.size();
        for (int i = 0; i < words.size(); i++) {
            if (words[i] == word1) {
                iter1 = i;
                if (iter2 != -1) {
                    res = std::min(res, iter1 - iter2);
                }
            } else if (words[i] == word2) {
                iter2 = i;
                if (iter1 != -1) {
                    res = std::min(res, iter2 - iter1);
                }
            }
        }
        return res;
    }
};

Java

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public class Solution {
    public int shortestDistance(String[] words, String word1, String word2) {
        if (words.length < 2) {
            return 0;
        }
        int first = -1, second = -1;
        int res = Integer.MAX_VALUE;
        for (int i = 0; i < words.length; i++) {
            if (words[i].equals(word1)) {
                first = i;
                if (second != -1) {
                    res = Math.min(res, Math.abs(second - first));
                }
            } else if (words[i].equals(word2)) {
                second = i;
                if (first != -1) {
                    res = Math.min(res, Math.abs(second - first));
                }
            }
        }
        return res;
    }
}