您的位置：首页 > 理论基础 > 数据结构算法

一道可以使用Trie高级数据结构解决的算法题

2008-04-14 07:11 281 查看

Problem Statement

You have been given a "word search" puzzle, which consists of a rectangular grid of letters, in which several words are hidden. Each word may begin anywhere in the puzzle, and may be oriented in any straight line horizontally, vertically, or diagonally. However, the words must all go down, right, or down-right. (see examples)

You are given a String[], grid, indicating the letters in the grid to be searched. Character j of element i of grid is the letter at row i, column j. You are also given a String[], wordList, indicating the words to be found in the grid. You are to return a String[] indicating the locations of each word within the grid.

The return value should have the same number of elements as wordList. Each element of wordList corresponds to the element of the return value with the same index.

Each element of the return value should be formatted as "row col" (quotes added for clarity), where row is the 0-based row in which the first letter of the word is found, and col is the 0-based column in which the first letter of the word is found. If the same word can be found more than once, the location in the lowest-indexed row should be returned. If there is still a tie, return the location with the lowest-indexed column. If a word cannot be found in the grid, return an empty string for that element.

Definition

Class:	WordFind
Method:	findWords
Parameters:	String[], String[]
Returns:	String[]
Method signature:	String[] findWords(String[] grid, String[] wordList)
(be sure your method is public)

Constraints

grid will contain between 1 and 50 elements, inclusive.

Each element of grid will contain between 1 and 50 characters, inclusive.

Each element of grid will contain the same number of characters.

Each character of each element of grid will be 'A'-'Z'.

wordList will contain between 1 and 50 elements, inclusive.

Each element of wordList will contain between 1 and 50 characters, inclusive.

Each character of each element of wordList will be 'A'-'Z'.

Examples

{"TEST",
"GOAT",
"BOAT"}

{"GOAT", "BOAT", "TEST"}

Returns: { "1 0",
"2 0",
"0 0" }

These words are pretty easy to find.

{"SXXX",
"XQXM",
"XXLA",
"XXXR"}

{"SQL", "RAM"}

Returns: { "0 0",
"" }

While "RAM" may be found going up at "3 3", we are only allowing words that go down and right.

{"EASYTOFINDEAGSRVHOTCJYG",
"FLVENKDHCESOXXXXFAGJKEO",
"YHEDYNAIRQGIZECGXQLKDBI",
"DEIJFKABAQSIHSNDLOMYJIN",
"CKXINIMMNGRNSNRGIWQLWOG",
"VOFQDROQGCWDKOUYRAFUCDO",
"PFLXWTYKOITSURQJGEGSPGG"}

{"EASYTOFIND", "DIAG", "GOING", "THISISTOOLONGTOFITINTHISPUZZLE"}

Returns: { "0 0",
"1 6",
"0 22",
"" }

My Solution：

因为数据量不是很大，直接暴力搜也可以通过。但是我还是用Trie写了一种解决方案。代码如下：

1//Use Trie to match word text pattern

2

53class Trie

54

109class WordFind

110

内容来自用户分享和网络整理，不保证内容的准确性，如有侵权内容，可联系管理员处理

标签：

相关文章推荐

新的分享

章节导航