添加（0654.最大二叉树.md）：增加typescript版本

problems/0654.最大二叉树.md

@@ -371,7 +371,56 @@ var constructMaximumBinaryTree = function (nums) {
 };
 ```
 
+## TypeScript
+
+> 新建数组法：
+
+```typescript
+function constructMaximumBinaryTree(nums: number[]): TreeNode | null {
+    if (nums.length === 0) return null;
+    let maxIndex: number = 0;
+    let maxVal: number = nums[0];
+    for (let i = 1, length = nums.length; i < length; i++) {
+        if (nums[i] > maxVal) {
+            maxIndex = i;
+            maxVal = nums[i];
+        }
+    }
+    const rootNode: TreeNode = new TreeNode(maxVal);
+    rootNode.left = constructMaximumBinaryTree(nums.slice(0, maxIndex));
+    rootNode.right = constructMaximumBinaryTree(nums.slice(maxIndex + 1));
+    return rootNode;
+};
+```
+
+> 使用数组索引法：
+
+```typescript
+function constructMaximumBinaryTree(nums: number[]): TreeNode | null {
+    // 左闭右开区间[begin, end)
+    function recur(nums: number[], begin: number, end: number): TreeNode | null {
+        if (begin === end) return null;
+        let maxIndex: number = begin;
+        let maxVal: number = nums[begin];
+        for (let i = begin + 1; i < end; i++) {
+            if (nums[i] > maxVal) {
+                maxIndex = i;
+                maxVal = nums[i];
+            }
+        }
+        const rootNode: TreeNode = new TreeNode(maxVal);
+        rootNode.left = recur(nums, begin, maxIndex);
+        rootNode.right = recur(nums, maxIndex + 1, end);
+        return rootNode;
+    }
+    return recur(nums, 0, nums.length);
+};
+```
+
+
+
 ## C
+
 ```c
 struct TreeNode* traversal(int* nums, int left, int right) {
     //若左边界大于右边界，返回NULL