backtracking.word_search ======================== .. py:module:: backtracking.word_search .. autoapi-nested-parse:: Author : Alexander Pantyukhin Date : November 24, 2022 Task: 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. Example: Matrix: --------- |A|B|C|E| |S|F|C|S| |A|D|E|E| --------- Word: "ABCCED" Result: True Implementation notes: Use backtracking approach. At each point, check all neighbors to try to find the next letter of the word. leetcode: https://leetcode.com/problems/word-search/ Functions --------- .. autoapisummary:: backtracking.word_search.exits_word backtracking.word_search.get_point_key backtracking.word_search.word_exists Module Contents --------------- .. py:function:: exits_word(board: list[list[str]], word: str, row: int, column: int, word_index: int, visited_points_set: set[int]) -> bool Return True if it's possible to search the word suffix starting from the word_index. >>> exits_word([["A"]], "B", 0, 0, 0, set()) False .. py:function:: get_point_key(len_board: int, len_board_column: int, row: int, column: int) -> int Returns the hash key of matrix indexes. >>> get_point_key(10, 20, 1, 0) 200 .. py:function:: word_exists(board: list[list[str]], word: str) -> bool >>> word_exists([["A","B","C","E"],["S","F","C","S"],["A","D","E","E"]], "ABCCED") True >>> word_exists([["A","B","C","E"],["S","F","C","S"],["A","D","E","E"]], "SEE") True >>> word_exists([["A","B","C","E"],["S","F","C","S"],["A","D","E","E"]], "ABCB") False >>> word_exists([["A"]], "A") True >>> word_exists([["B", "A", "A"], ["A", "A", "A"], ["A", "B", "A"]], "ABB") False >>> word_exists([["A"]], 123) Traceback (most recent call last): ... ValueError: The word parameter should be a string of length greater than 0. >>> word_exists([["A"]], "") Traceback (most recent call last): ... ValueError: The word parameter should be a string of length greater than 0. >>> word_exists([[]], "AB") Traceback (most recent call last): ... ValueError: The board should be a non empty matrix of single chars strings. >>> word_exists([], "AB") Traceback (most recent call last): ... ValueError: The board should be a non empty matrix of single chars strings. >>> word_exists([["A"], [21]], "AB") Traceback (most recent call last): ... ValueError: The board should be a non empty matrix of single chars strings.