265th Commit

Author: Shyam-Chen

README.md

@@ -581,12 +581,13 @@ Problems:
 | ----------------------------------- | --------------- | ------ | ---- |
 | 70. Climbing Stairs                 | [Solution][70]  | Easy   | 詳解 |
 | 198. House Robber                   | [Solution][198] | Medium | 詳解 |
-| 139. Word Break                     | Solution        | Medium | 詳解 |
+| 139. Word Break                     | [Solution][139] | Medium | 詳解 |
 | 322. Coin Change                    | Solution        | Medium | 詳解 |
 | 300. Longest Increasing Subsequence | Solution        | Medium | 詳解 |
 
 [70]: ./src/page-1/70.%20Climbing%20Stairs/climbStairs.ts
 [198]: ./src/page-2/198.%20House%20Robber/rob.ts
+[139]: ./src/page-2/139.%20Word%20Break/wordBreak.ts
 
 | Multidimensional DP                      |                |        |                        |
 | ---------------------------------------- | -------------- | ------ | ---------------------- |
@@ -676,7 +677,7 @@ Problems:
 | 70. Climbing Stairs                 | [Solution][70]   | Easy   | 詳解                   |
 | 72. Edit Distance                   | [Solution][72]   | Medium | [詳解][72-explanation] |
 | 118. Pascal's Triangle              | [Solution][118]  | Easy   | 詳解                   |
-| 139. Word Break                     | Solution         | Medium | 詳解                   |
+| 139. Word Break                     | [Solution][139]  | Medium | 詳解                   |
 | 152. Maximum Product Subarray       | Solution         | Medium | 詳解                   |
 | 198. House Robber                   | [Solution][198]  | Medium | 詳解                   |
 | 279. Perfect Squares                | Solution         | Medium | 詳解                   |
@@ -691,6 +692,7 @@ Problems:
 [72]: ./src/page-1/72.%20Edit%20Distance/minDistance.ts
 [72-explanation]: ./src/page-1/72.%20Edit%20Distance/README.md
 [118]: ./src/page-2/118.%20Pascal's%20Triangle/generate.ts
+[139]: ./src/page-2/139.%20Word%20Break/wordBreak.ts
 [198]: ./src/page-2/198.%20House%20Robber/rob.ts
 [1143]: ./src/page-11/1143.%20Longest%20Common%20Subsequence/longestCommonSubsequence.ts
 

src/page-2/139. Word Break/wordBreak.test.ts

@@ -0,0 +1,23 @@
+import { wordBreak } from './wordBreak';
+
+describe('139. Word Break', () => {
+  test('wordBreak', () => {
+    {
+      const s = 'leetcode';
+      const wordDict = ['leet', 'code'];
+      expect(wordBreak(s, wordDict)).toBe(true);
+    }
+
+    {
+      const s = 'applepenapple';
+      const wordDict = ['apple', 'pen'];
+      expect(wordBreak(s, wordDict)).toBe(true);
+    }
+
+    {
+      const s = 'catsandog';
+      const wordDict = ['cats', 'dog', 'sand', 'and', 'cat'];
+      expect(wordBreak(s, wordDict)).toBe(false);
+    }
+  });
+});

src/page-2/139. Word Break/wordBreak.ts

@@ -0,0 +1,22 @@
+type WordBreak = (s: string, wordDict: string[]) => boolean;
+
+/**
+ * Accepted
+ */
+export const wordBreak: WordBreak = (s, wordDict) => {
+  const wordSet = new Set(wordDict);
+  const dp: boolean[] = Array(s.length + 1).fill(false);
+
+  dp[0] = true;
+
+  for (let i = 1; i <= s.length; i++) {
+    for (let j = 0; j < i; j++) {
+      if (dp[j] && wordSet.has(s.substring(j, i))) {
+        dp[i] = true;
+        break;
+      }
+    }
+  }
+
+  return dp[s.length];
+};