Word Search II

Given a 2-D character grid and a list of up to 30,000 words, return every word that can be traced along a path of horizontally or vertically adjacent cells, with no cell reused within a single word. This is the LeetCode 212 family: a naive per-word search blows up, so the intended solution builds a trie over the word list and runs a single grid DFS with backtracking, pruning branches that fall off the trie. Word Search II Given a 2-D character grid and a list of up to 30,000 words, return every word that can be traced along a path of horizontally or vertically adjacent cells, with no cell reused within a single word. This is the LeetCode 212 family: a naive per-word search blows up, so the intended solution builds a trie over the word list and runs a single grid DFS with backtracking, pruning branches that fall off the trie. SWE trie grid dfs backtracking string hard Frequency Single report Last asked 2026-03-23 Stage onsite-coding Word Search II Given a 2-D grid of characters board and a list of strings words, return all words that are present in the grid. For a word to be present it must be possible to form the word with a path in the board with horizontally or vertically neighboring cells. The same cell may not be used more than once in a word. Examples Example 1: Input: board = [ ["a","b","c","d"], ["s","a","a","t"], ["a","c","k","e"], ["a","c","d","n"] ], words = ["bat","cat","back","backend","stack"] Output: ["cat","back","backend"] Example 2: Input: board = [ ["x","o"], ["x","o"] ], words = ["xoxo"] Output: [] Constraints 1 <= board.length, board[i].length <= 12 board[i] consists only of lowercase English letters. 1 <= words.length <= 30,000 1 <= words[i].length <= 10 words[i] consists only of lowercase English letters. All strings within words are distinct.