Given a string text and an array of strings words, return a list of all index pairs [i, j] such that the substring text[i...j] is present in words.

Return the pairs [i, j] in sorted order, first by the value of i, and if two pairs have the same i, by the value of j.

Constraints:

• $1 \leq$ text.length $\leq 100$

• $1 \leq$ words.length $\leq 20$

• $1 \leq$ words[i].length $\leq 50$

• text and words[i] consist of lowercase English letters.

• All the strings of words are unique.

The algorithm uses a trie to find all pairs of start and end indexes for substrings in a given text that match words from a list. First, it builds the trie by inserting each word from the list. Then, it iterates over each starting index in the text to match substrings using the trie. For each character sequence, it checks if the current character exists in the trie and traverses accordingly. If a word’s end is found (marked by a flag), the start and end indexes of the matched substring are recorded in the result. This method optimizes substring searching using the trie structure to avoid redundant checks and efficiently match multiple words in the text.

TrieNode and Trie Class

• TrieNode: This represents a single character in the trie with two components: is_end_of_word (a boolean indicating if the node ...