Add Balanced Binary Tree TS Solution

Author: JeremyXXXuuu

Problems/03-Balanced-Binary-Tree/Balanced-Binary-Tree.ts

@@ -0,0 +1,20 @@
+function isBalanced(root: TreeNode | null): boolean {
+    if (!root) {
+        return true;
+    }
+    console.log(balance(root));
+    return balance(root) !== -1
+
+    //自底至顶 后续遍历
+    function balance(root: TreeNode | null): number {
+        if (!root) {
+            return 0;
+        }
+        let leftDepth = balance(root.left);
+        if (leftDepth == -1) return -1;
+        let rightDepth = balance(root.right);
+        if (rightDepth == -1) return -1;
+        if (Math.abs(leftDepth - rightDepth) > 1) return -1;
+        return 1 + Math.max(leftDepth, rightDepth);
+    }
+};