Create 面试题07. 重建二叉树.js

Author: yinxin630

面试题07. 重建二叉树.js

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+/**
+ * Definition for a binary tree node.
+ * function TreeNode(val) {
+ *     this.val = val;
+ *     this.left = this.right = null;
+ * }
+ */
+/**
+ * @param {number[]} preorder
+ * @param {number[]} inorder
+ * @return {TreeNode}
+ */
+var buildTree = function(preorder, inorder) {
+    if (preorder.length === 0) {
+        return null;
+    }
+    const node = new TreeNode(preorder[0]);
+    const index = inorder.indexOf(preorder[0]);
+    const leftPreorder = preorder.slice(1, index + 1);
+    node.left = leftPreorder.length ? buildTree(leftPreorder, inorder.slice(0, index)) : null;
+    const rightPreorder = preorder.slice(index + 1);
+    node.right = rightPreorder.length ? buildTree(rightPreorder, inorder.slice(index + 1)) : null;
+    return node;
+};