feat: add ts solution to lc problem: No.0127

solution/0100-0199/0127.Word Ladder/README.md

@@ -310,6 +310,57 @@ public class Solution {
 }
 ```
 
+#### TypeScript
+
+```ts
+function ladderLength(beginWord: string, endWord: string, wordList: string[]): number {
+    if (!wordList.includes(endWord)) return 0;
+
+    const replace = (s: string, i: number, ch: string) => s.slice(0, i) + ch + s.slice(i + 1);
+    const { length } = beginWord;
+    const words: Record<string, string[]> = {};
+    const g: Record<string, string[]> = {};
+
+    for (const w of [beginWord, ...wordList]) {
+        const derivatives: string[] = [];
+
+        for (let i = 0; i < length; i++) {
+            const nextW = replace(w, i, '*');
+            derivatives.push(nextW);
+
+            g[nextW] ??= [];
+            g[nextW].push(w);
+        }
+
+        words[w] = derivatives;
+    }
+
+    let ans = 0;
+    let q = words[beginWord];
+    const vis = new Set<string>([beginWord]);
+
+    while (q.length) {
+        const nextQ: string[] = [];
+        ans++;
+
+        for (const variant of q) {
+            for (const w of g[variant]) {
+                if (w === endWord) return ans + 1;
+
+                if (vis.has(w)) continue;
+                vis.add(w);
+
+                nextQ.push(...words[w]);
+            }
+        }
+
+        q = nextQ;
+    }
+
+    return 0;
+}
+```
+
 <!-- tabs:end -->
 
 <!-- solution:end -->

solution/0100-0199/0127.Word Ladder/README_EN.md

@@ -310,6 +310,57 @@ public class Solution {
 }
 ```
 
+#### TypeScript
+
+```ts
+function ladderLength(beginWord: string, endWord: string, wordList: string[]): number {
+    if (!wordList.includes(endWord)) return 0;
+
+    const replace = (s: string, i: number, ch: string) => s.slice(0, i) + ch + s.slice(i + 1);
+    const { length } = beginWord;
+    const words: Record<string, string[]> = {};
+    const g: Record<string, string[]> = {};
+
+    for (const w of [beginWord, ...wordList]) {
+        const derivatives: string[] = [];
+
+        for (let i = 0; i < length; i++) {
+            const nextW = replace(w, i, '*');
+            derivatives.push(nextW);
+
+            g[nextW] ??= [];
+            g[nextW].push(w);
+        }
+
+        words[w] = derivatives;
+    }
+
+    let ans = 0;
+    let q = words[beginWord];
+    const vis = new Set<string>([beginWord]);
+
+    while (q.length) {
+        const nextQ: string[] = [];
+        ans++;
+
+        for (const variant of q) {
+            for (const w of g[variant]) {
+                if (w === endWord) return ans + 1;
+
+                if (vis.has(w)) continue;
+                vis.add(w);
+
+                nextQ.push(...words[w]);
+            }
+        }
+
+        q = nextQ;
+    }
+
+    return 0;
+}
+```
+
 <!-- tabs:end -->
 
 <!-- solution:end -->

solution/0100-0199/0127.Word Ladder/Solution.ts

@@ -0,0 +1,46 @@
+function ladderLength(beginWord: string, endWord: string, wordList: string[]): number {
+    if (!wordList.includes(endWord)) return 0;
+
+    const replace = (s: string, i: number, ch: string) => s.slice(0, i) + ch + s.slice(i + 1);
+    const { length } = beginWord;
+    const words: Record<string, string[]> = {};
+    const g: Record<string, string[]> = {};
+
+    for (const w of [beginWord, ...wordList]) {
+        const derivatives: string[] = [];
+
+        for (let i = 0; i < length; i++) {
+            const nextW = replace(w, i, '*');
+            derivatives.push(nextW);
+
+            g[nextW] ??= [];
+            g[nextW].push(w);
+        }
+
+        words[w] = derivatives;
+    }
+
+    let ans = 0;
+    let q = words[beginWord];
+    const vis = new Set<string>([beginWord]);
+
+    while (q.length) {
+        const nextQ: string[] = [];
+        ans++;
+
+        for (const variant of q) {
+            for (const w of g[variant]) {
+                if (w === endWord) return ans + 1;
+
+                if (vis.has(w)) continue;
+                vis.add(w);
+
+                nextQ.push(...words[w]);
+            }
+        }
+
+        q = nextQ;
+    }
+
+    return 0;
+}