[leetcode] 243. Shortest Word Distance 解题报告

题目链接:https://leetcode.com/problems/shortest-word-distance/

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.




思路: 需要注意的是可能两个单词都会在字典里出现很多次, 因此我们可以用hash table保存一个单词的多个位置, 然后枚举最小的距离.
代码如下:

class Solution {
public:
    int shortestDistance(vector<string>& words, string word1, string word2) {
        unordered_map<string, vector<int>> mp;
        for(int i =0; i< words.size(); i++)
            mp[words[i]].push_back(i);
        int Min = INT_MAX;
        for(auto val1: mp[word1])
            for(auto val2: mp[word2])
                Min = min(Min, abs(val1 - val2));
        return Min;
    }
};