add tree

Author: Ehco1996

ehco/tree/tree.py

@@ -0,0 +1,41 @@
+class Node:
+    def __init__(self, val=None, left=None, right=None):
+        self.val = val
+        self.left = left
+        self.right = right
+
+    def __str__(self):
+        return f"Node:{self.val}"
+
+    __repr__ = __str__
+
+
+class Tree:
+    def __init__(self, root):
+        self.root = root
+
+    @classmethod
+    def build_tree_from_array(cls, array):
+        # array BFS
+
+        lens = len(array)
+        node_list = [Node(val) for val in array]
+        t = cls(node_list[0])
+        for idx, node in enumerate(node_list):
+            left_idx = 2 * idx + 1
+            right_idx = 2 * idx + 2
+            if left_idx < lens:
+                node.left = node_list[left_idx]
+            if right_idx < lens:
+                node.right = node_list[right_idx]
+        return t
+
+    def bfs(self):
+        queue = [self.root]
+        res = []
+        while queue:
+            cur = queue.pop(0)
+            res.append(cur.val)
+            cur.left and queue.append(cur.left)
+            cur.right and queue.append(cur.right)
+        return res