mediumTries

Word Search

## Problem

Given an `m x n` grid of characters `board` and a string `word`, return `true` if `word` exists in the grid.

The word can be constructed from letters of sequentially adjacent cells, where adjacent cells are horizontally or vertically neighboring. The same letter cell may not be used more than once.

Examples

Input

board = [["A","B","C","E"],["S","F","C","S"],["A","D","E","E"]], word = "ABCCED"

Output

true

Path: A→B→C→C→E→D.

Input

board = [["A","B","C","E"],["S","F","C","S"],["A","D","E","E"]], word = "SEE"

Output

true

Path: S→E→E (bottom right).

Input

board = [["A","B","C","E"],["S","F","C","S"],["A","D","E","E"]], word = "ABCB"

Output

false

Cannot reuse B.

Constraints

m == board.length n = board[i].length 1 <= m, n <= 6 1 <= word.length <= 15 board and word consists of only lowercase and uppercase English letters.

Python