README_EN.md

1268. Search Suggestions System

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Description

You are given an array of strings products and a string searchWord.

Design a system that suggests at most three product names from products after each character of searchWord is typed. Suggested products should have common prefix with searchWord. If there are more than three products with a common prefix return the three lexicographically minimums products.

Return a list of lists of the suggested products after each character of searchWord is typed.

 

Example 1:

Input: products = ["mobile","mouse","moneypot","monitor","mousepad"], searchWord = "mouse"
Output: [["mobile","moneypot","monitor"],["mobile","moneypot","monitor"],["mouse","mousepad"],["mouse","mousepad"],["mouse","mousepad"]]
Explanation: products sorted lexicographically = ["mobile","moneypot","monitor","mouse","mousepad"].
After typing m and mo all products match and we show user ["mobile","moneypot","monitor"].
After typing mou, mous and mouse the system suggests ["mouse","mousepad"].

Example 2:

Input: products = ["havana"], searchWord = "havana"
Output: [["havana"],["havana"],["havana"],["havana"],["havana"],["havana"]]
Explanation: The only word "havana" will be always suggested while typing the search word.

 

Constraints:

• 1 <= products.length <= 1000
• 1 <= products[i].length <= 3000
• 1 <= sum(products[i].length) <= 2 * 104
• All the strings of products are unique.
• products[i] consists of lowercase English letters.
• 1 <= searchWord.length <= 1000
• searchWord consists of lowercase English letters.

Solutions

Python3

class Trie:
    def __init__(self):
        self.children = [None] * 26
        self.v = []

    def insert(self, word, i):
        node = self
        for c in word:
            idx = ord(c) - ord('a')
            if node.children[idx] is None:
                node.children[idx] = Trie()
            node = node.children[idx]
            node.v.append(i)

    def search(self, word):
        res = [[] for _ in range(len(word))]
        node = self
        for i, c in enumerate(word):
            idx = ord(c) - ord('a')
            if node.children[idx] is None:
                break
            node = node.children[idx]
            res[i] = node.v[:3]
        return res


class Solution:
    def suggestedProducts(
        self, products: List[str], searchWord: str
    ) -> List[List[str]]:
        products.sort()
        trie = Trie()
        for i, w in enumerate(products):
            trie.insert(w, i)
        res = trie.search(searchWord)
        return [[products[j] for j in v] for v in res]

Java

class Trie {
    Trie[] children = new Trie[26];
    List<Integer> v = new ArrayList<>();

    void insert(String word, int i) {
        Trie node = this;
        for (char c : word.toCharArray()) {
            c -= 'a';
            if (node.children[c] == null) {
                node.children[c] = new Trie();
            }
            node = node.children[c];
            if (node.v.size() < 3) {
                node.v.add(i);
            }
        }
    }

    List<List<Integer>> search(String word) {
        List<List<Integer>> res = new ArrayList<>();
        int n = word.length();
        for (int i = 0; i < n; ++i) {
            res.add(new ArrayList<>());
        }
        Trie node = this;
        for (int i = 0; i < n; ++i) {
            char c = word.charAt(i);
            c -= 'a';
            if (node.children[c] == null) {
                break;
            }
            node = node.children[c];
            res.set(i, node.v);
        }
        return res;
    }
}

class Solution {
    public List<List<String>> suggestedProducts(String[] products, String searchWord) {
        Arrays.sort(products);
        Trie trie = new Trie();
        for (int i = 0; i < products.length; ++i) {
            trie.insert(products[i], i);
        }
        List<List<Integer>> res = trie.search(searchWord);
        List<List<String>> ans = new ArrayList<>();
        for (List<Integer> v : res) {
            List<String> t = new ArrayList<>();
            for (int i : v) {
                t.add(products[i]);
            }
            ans.add(t);
        }
        return ans;
    }
}

Go

type Trie struct {
	children [26]*Trie
	v        []int
}

func newTrie() *Trie {
	return &Trie{}
}
func (this *Trie) insert(word string, i int) {
	node := this
	for _, c := range word {
		c -= 'a'
		if node.children[c] == nil {
			node.children[c] = newTrie()
		}
		node = node.children[c]
		if len(node.v) < 3 {
			node.v = append(node.v, i)
		}
	}
}

func (this *Trie) search(word string) [][]int {
	node := this
	n := len(word)
	res := make([][]int, n)
	for i, c := range word {
		c -= 'a'
		if node.children[c] == nil {
			break
		}
		node = node.children[c]
		res[i] = node.v
	}
	return res
}

func suggestedProducts(products []string, searchWord string) [][]string {
	sort.Strings(products)
	trie := newTrie()
	for i, w := range products {
		trie.insert(w, i)
	}
	res := trie.search(searchWord)
	var ans [][]string
	for _, v := range res {
		t := []string{}
		for _, i := range v {
			t = append(t, products[i])
		}
		ans = append(ans, t)
	}
	return ans
}

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