From 8605f26bd762cd734e697ba7da9b3085d8f9db4d Mon Sep 17 00:00:00 2001
From: jerryfishcode <91447694+jerryfishcode@users.noreply.github.com>
Date: Tue, 28 Sep 2021 11:43:20 +0800
Subject: [PATCH] =?UTF-8?q?=E6=96=B0=E5=A2=9E127.=20=E5=8D=95=E8=AF=8D?=
 =?UTF-8?q?=E6=8E=A5=E9=BE=99=20JavaScript=E7=89=88=E6=9C=AC?=
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---
 problems/0127.单词接龙.md | 34 ++++++++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)

diff --git a/problems/0127.单词接龙.md b/problems/0127.单词接龙.md
index e38453ef..c52f2ba5 100644
--- a/problems/0127.单词接龙.md
+++ b/problems/0127.单词接龙.md
@@ -141,6 +141,40 @@ public int ladderLength(String beginWord, String endWord, List<String> wordList)
 ## Go 
 
 ## JavaScript
+```javascript
+var ladderLength = function(beginWord, endWord, wordList) {
+    // 将wordList转成Set，提高查询速度
+    const wordSet = new Set(wordList);
+    // Set元素个数为0 或者 endWord没有在wordSet出现，直接返回0
+    if (wordSet.size === 0 || !wordSet.has(endWord)) return 0;
+    // 记录word是否访问过
+    const visitMap = new Map();// <word, 查询到这个word路径长度>
+    // 初始化队列
+    const queue = [];
+    queue.push(beginWord);
+    // 初始化visitMap
+    visitMap.set(beginWord, 1);
+    
+    while(queue.length !== 0){
+        let word = queue.shift(); // 删除队首元素,将它的值存放在word
+        let path = visitMap.get(word); // 这个word的路径长度
+        for(let i = 0; i < word.length; i++){ // 遍历单词的每个字符
+            for (let c = 97; c <= 122; c++) { // 对应26个字母ASCII值 从'a' 到 'z' 遍历替换
+                // 拼串得到新的字符串
+                let newWord = word.slice(0, i) + String.fromCharCode(c) + word.slice(i + 1);
+                if(newWord === endWord) return path + 1; // 找到了end，返回path+1
+                // wordSet出现了newWord，并且newWord没有被访问过
+                if(wordSet.has(newWord) && !visitMap.has(newWord)) {
+                    // 添加访问信息
+                    visitMap.set(newWord, path + 1);
+                    queue.push(newWord);
+                }
+            }
+        }
+    }
+    return 0;
+};
+```
 
 
 -----------------------