Merge pull request #1295 from xiaofei-2020/dp26

添加（0139.单词拆分.md）:增加typescript版本

problems/0139.单词拆分.md

@@ -345,6 +345,48 @@ const wordBreak = (s, wordDict) => {
 }
 ```
 
+TypeScript：
+
+> 动态规划
+
+```typescript
+function wordBreak(s: string, wordDict: string[]): boolean {
+    const dp: boolean[] = new Array(s.length + 1).fill(false);
+    dp[0] = true;
+    for (let i = 1; i <= s.length; i++) {
+        for (let j = 0; j < i; j++) {
+            const tempStr: string = s.slice(j, i);
+            if (wordDict.includes(tempStr) && dp[j] === true) {
+                dp[i] = true;
+                break;
+            }
+        }
+    }
+    return dp[s.length];
+};
+```
+
+> 记忆化回溯
+
+```typescript
+function wordBreak(s: string, wordDict: string[]): boolean {
+    // 只需要记忆结果为false的情况
+    const memory: boolean[] = [];
+    return backTracking(s, wordDict, 0, memory);
+    function backTracking(s: string, wordDict: string[], startIndex: number, memory: boolean[]): boolean {
+        if (startIndex >= s.length) return true;
+        if (memory[startIndex] === false) return false;
+        for (let i = startIndex + 1, length = s.length; i <= length; i++) {
+            const str: string = s.slice(startIndex, i);
+            if (wordDict.includes(str) && backTracking(s, wordDict, i, memory))
+                return true;
+        }
+        memory[startIndex] = false;
+        return false;
+    }
+};
+```
+
 
 
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