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244. Shortest Word Distance II πŸ”’

Description

Design a data structure that will be initialized with a string array, and then it should answer queries of the shortest distance between two different strings from the array.

Implement the WordDistance class:

  • WordDistance(String[] wordsDict) initializes the object with the strings array wordsDict.
  • int shortest(String word1, String word2) returns the shortest distance between word1 and word2 in the array wordsDict.

 

Example 1:

Input
["WordDistance", "shortest", "shortest"]
[[["practice", "makes", "perfect", "coding", "makes"]], ["coding", "practice"], ["makes", "coding"]]
Output
[null, 3, 1]

Explanation
WordDistance wordDistance = new WordDistance(["practice", "makes", "perfect", "coding", "makes"]);
wordDistance.shortest("coding", "practice"); // return 3
wordDistance.shortest("makes", "coding");    // return 1

 

Constraints:

  • 1 <= wordsDict.length <= 3 * 104
  • 1 <= wordsDict[i].length <= 10
  • wordsDict[i] consists of lowercase English letters.
  • word1 and word2 are in wordsDict.
  • word1 != word2
  • At most 5000 calls will be made to shortest.

Solutions

Solution 1

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class WordDistance:
    def __init__(self, wordsDict: List[str]):
        self.d = defaultdict(list)
        for i, w in enumerate(wordsDict):
            self.d[w].append(i)

    def shortest(self, word1: str, word2: str) -> int:
        a, b = self.d[word1], self.d[word2]
        ans = inf
        i = j = 0
        while i < len(a) and j < len(b):
            ans = min(ans, abs(a[i] - b[j]))
            if a[i] <= b[j]:
                i += 1
            else:
                j += 1
        return ans


# Your WordDistance object will be instantiated and called as such:
# obj = WordDistance(wordsDict)
# param_1 = obj.shortest(word1,word2)

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class WordDistance {
    private Map<String, List<Integer>> d = new HashMap<>();

    public WordDistance(String[] wordsDict) {
        for (int i = 0; i < wordsDict.length; ++i) {
            d.computeIfAbsent(wordsDict[i], k -> new ArrayList<>()).add(i);
        }
    }

    public int shortest(String word1, String word2) {
        List<Integer> a = d.get(word1), b = d.get(word2);
        int ans = 0x3f3f3f3f;
        int i = 0, j = 0;
        while (i < a.size() && j < b.size()) {
            ans = Math.min(ans, Math.abs(a.get(i) - b.get(j)));
            if (a.get(i) <= b.get(j)) {
                ++i;
            } else {
                ++j;
            }
        }
        return ans;
    }
}

/**
 * Your WordDistance object will be instantiated and called as such:
 * WordDistance obj = new WordDistance(wordsDict);
 * int param_1 = obj.shortest(word1,word2);
 */

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class WordDistance {
public:
    WordDistance(vector<string>& wordsDict) {
        for (int i = 0; i < wordsDict.size(); ++i) {
            d[wordsDict[i]].push_back(i);
        }
    }

    int shortest(string word1, string word2) {
        auto a = d[word1], b = d[word2];
        int i = 0, j = 0;
        int ans = INT_MAX;
        while (i < a.size() && j < b.size()) {
            ans = min(ans, abs(a[i] - b[j]));
            if (a[i] <= b[j]) {
                ++i;
            } else {
                ++j;
            }
        }
        return ans;
    }

private:
    unordered_map<string, vector<int>> d;
};

/**
 * Your WordDistance object will be instantiated and called as such:
 * WordDistance* obj = new WordDistance(wordsDict);
 * int param_1 = obj->shortest(word1,word2);
 */

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type WordDistance struct {
    d map[string][]int
}

func Constructor(wordsDict []string) WordDistance {
    d := map[string][]int{}
    for i, w := range wordsDict {
        d[w] = append(d[w], i)
    }
    return WordDistance{d}
}

func (this *WordDistance) Shortest(word1 string, word2 string) int {
    a, b := this.d[word1], this.d[word2]
    ans := 0x3f3f3f3f
    i, j := 0, 0
    for i < len(a) && j < len(b) {
        ans = min(ans, abs(a[i]-b[j]))
        if a[i] <= b[j] {
            i++
        } else {
            j++
        }
    }
    return ans
}

func abs(x int) int {
    if x < 0 {
        return -x
    }
    return x
}

/**
 * Your WordDistance object will be instantiated and called as such:
 * obj := Constructor(wordsDict);
 * param_1 := obj.Shortest(word1,word2);
 */

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