feat: add ts solution to lcof problem: No.33

面试题33. 二叉搜索树的后序遍历序列

Author: YangFong

lcof/面试题33. 二叉搜索树的后序遍历序列/README.md

@@ -171,6 +171,31 @@ public:
 };
 ```
 
+### **TypeScript**
+
+```ts
+function verifyPostorder(postorder: number[]): boolean {
+    const dfs = (start: number, end: number, maxVal: number) => {
+        if (start > end) {
+            return true;
+        }
+        const rootVal = postorder[end];
+        for (let i = end; i >= start; i--) {
+            const val = postorder[i];
+            if (val > maxVal) {
+                return false;
+            }
+            if (val < rootVal) {
+                return dfs(start, i, rootVal) && dfs(i + 1, end - 1, maxVal);
+            }
+        }
+        return dfs(start, end - 1, maxVal);
+    };
+    const n = postorder.length;
+    return dfs(0, n - 1, Infinity);
+}
+```
+
 ### **...**
 
 ```

lcof/面试题33. 二叉搜索树的后序遍历序列/Solution.ts

@@ -0,0 +1,20 @@
+function verifyPostorder(postorder: number[]): boolean {
+    const dfs = (start: number, end: number, maxVal: number) => {
+        if (start > end) {
+            return true;
+        }
+        const rootVal = postorder[end];
+        for (let i = end; i >= start; i--) {
+            const val = postorder[i];
+            if (val > maxVal) {
+                return false;
+            }
+            if (val < rootVal) {
+                return dfs(start, i, rootVal) && dfs(i + 1, end - 1, maxVal);
+            }
+        }
+        return dfs(start, end - 1, maxVal);
+    };
+    const n = postorder.length;
+    return dfs(0, n - 1, Infinity);
+}