# 1268. Search Suggestions System

Given an array of strings products and a string searchWord. We want to 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 the searchWord. If there are more than three products with a common prefix return the three lexicographically minimums products.

Return 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"]]

Example 3:

Input: products = ["bags","baggage","banner","box","cloths"], searchWord = "bags"
Output: [["baggage","bags","banner"],["baggage","bags","banner"],["baggage","bags"],["bags"]]

Example 4:

Input: products = ["havana"], searchWord = "tatiana"
Output: [[],[],[],[],[],[],[]]

# Solution

Approach 1: sort, then close on the relevant buckets as the number of characters come by.

Approach 2: trie (prefix tree) -- but need to store the suggestions in each node.

# Code (Python)

Approach 1:

    def suggestedProducts(self, products: List[str], search_word: str) -> List[List[str]]:
        relevant = sorted(products)
        result = []
        for i, letter in enumerate(search_word):
            # can also do binary search to get the relevant bracket; the bracket can be pointers to save space
            relevant = sorted(filter(lambda word: word.startswith(search_word[:i + 1]), relevant))
            result.append([_ for _ in relevant[:3]] if len(relevant) >= 3 else [_ for _ in relevant])
        return result

Approach 2:

class TrieNode:
    def __init__(self):
        self.suggestions = []
        self.children = {}

class Solution:    
    def suggestedProducts(self, products: List[str], search_word: str) -> List[List[str]]:
        root = TrieNode()
        for word in products:
            node = root
            for letter in word:
                if letter not in node.children:
                    node.children[letter] = TrieNode()
                node = node.children[letter]
                node.suggestions.append(word)
                node.suggestions = sorted(node.suggestions)[:3] if len(node.suggestions) >= 3 else sorted(node.suggestions)
        
        result = []
        node = root
        for letter in search_word:
            if letter not in node.children:
                return result + [[]] * (len(search_word) - len(result))
            node = node.children[letter]
            result.append(node.suggestions)
        return result

# Code (C++)

Approach 1:

Approach 2: