-
Notifications
You must be signed in to change notification settings - Fork 0
/
wordLadder.js
84 lines (64 loc) · 2.07 KB
/
wordLadder.js
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
// 127. Word Ladder
// Medium
// Given two words (beginWord and endWord), and a dictionary's word list, find the length of shortest transformation sequence from beginWord to endWord, such that:
// Only one letter can be changed at a time.
// Each transformed word must exist in the word list.
// Note:
// Return 0 if there is no such transformation sequence.
// All words have the same length.
// All words contain only lowercase alphabetic characters.
// You may assume no duplicates in the word list.
// You may assume beginWord and endWord are non-empty and are not the same.
// Example 1:
// Input:
// beginWord = "hit",
// endWord = "cog",
// wordList = ["hot","dot","dog","lot","log","cog"]
// Output: 5
// Explanation: As one shortest transformation is "hit" -> "hot" -> "dot" -> "dog" -> "cog",
// return its length 5.
// Example 2:
// Input:
// beginWord = "hit"
// endWord = "cog"
// wordList = ["hot","dot","dog","lot","log"]
// Output: 0
// Explanation: The endWord "cog" is not in wordList, therefore no possible transformation.
/**
* @param {string} beginWord
* @param {string} endWord
* @param {string[]} wordList
* @return {number}
*/
// use distance hash
var ladderLength = function(beginWord, endWord, wordList) {
const queue = [beginWord]
const distance = {[beginWord]: 1}
while(queue.length > 0) {
const curWord = queue.shift()
if (curWord === endWord){
return distance[curWord]
}
for ( let nextWord of getNextWords(curWord)) {
if( wordList.indexOf(nextWord) === -1 || distance.hasOwnProperty(nextWord)) {
continue;
}
queue.push(nextWord)
distance[nextWord] = distance[curWord] + 1
}
}
return 0
};
function getNextWords (word) {
const words = [];
const engLetters = 'abcdefghijklmnopqrstuvwxyz'
for(let i = 0; i < word.length; i++) {
for(let j = 0; j < engLetters.length; j++) {
if(engLetters[j] === word[i]){
continue;
}
words.push( word.slice(0,i) + engLetters[j] + word.slice(i+1))
}
}
return words
}