Search Suggestion System (Trie)

Ronald — Thu, 14 May 2020 03:08:02 +0000
let suggestedProducts = function(products, searchWord) {
    const MAX_RESULT_COUNT = 3;
    let root = {
        children: {}
    };

    function addToNode(word, index, node) {
        if (index >= word.length) {
            node.end = true;
            return;
        }
        //
        const child = node.children[word[index]];
        if (child) {
            addToNode(word, index + 1, child);
        }
        else {
            let child = {val: word[index], parent: node, children: {}};
            node.children[word[index]] = child;
            addToNode(word, index + 1, child);
        }
    }

    function getWord(leaf) {
        let node = leaf;
        let str = '';
        while (node) {
            if (node.val) str = node.val + str; //?
            node = node.parent; //?
        }

        return str; //?
    }

    function searchProducts(searchString) {

        let words = [];
        let nodes = [...Object.entries(root.children)], len = searchString.length;
        while (nodes.length) {

            let currentNodeLength = nodes.length;
            while (currentNodeLength > 0) {
                currentNodeLength--;

                const node = nodes.pop();
                const [key, val] = node;
                if (len > 0 && key === searchString[searchString.length - len]) {
                    nodes.unshift(...Object.entries(val.children));

                    if (len === 1 && val.end) {
                        words.push(getWord(val));
                    }
                } else if (len <= 0) {
                    if (val.end) words.push(getWord(val));
                    nodes.unshift(...Object.entries(val.children));
                }
            }
            len--;
        }

        return words.sort().slice(0, Math.min(MAX_RESULT_COUNT, words.length));
    }

    for(let product of products) {
        addToNode(product, 0, root);
    }


    let result = [];
    for (let i = 0; i < searchWord.length; i++) {
        result.push(searchProducts(searchWord.substring(0, i + 1))); //?
    }

    return result; //?
};
trie – JSAlgorithm

Search Suggestion System (Trie)
