32.py

HSKIM/31to40/32.py

@@ -0,0 +1,76 @@
+from collections import deque
+
+
+class Node:
+    def __init__(self, info, num, left=None, right=None):
+        self.info = info
+        self.left = left
+        self.right = right
+        self.num = num
+
+    def has_left(self):
+        return self.left is not None
+
+    def has_right(self):
+        return self.right is not None
+
+def build_binary_tree(nodeinfo):
+    nodes = [i for i in range(1, len(nodeinfo) + 1)]
+    nodes.sort(key=lambda x: (nodeinfo[x-1][1], -nodeinfo[x-1][0]), reverse=True)
+    root = None
+
+    for i in range(len(nodes)):
+        if root is None:
+            root = Node(nodeinfo[nodes[0] - 1], nodes[0])
+        else:
+            parent = root
+            node = Node(nodeinfo[nodes[i] - 1], nodes[i])
+
+            while True:
+                if node.info[0] < parent.info[0]:
+                    if parent.has_left():
+                        parent = parent.left
+                        continue
+                    parent.left = node
+                    break
+                else:
+                    if parent.has_right():
+                        parent = parent.right
+                        continue
+                    parent.right = node
+                    break
+    return root
+
+def pre_order(root, answer):
+    stack = [root]
+    while stack:
+        node = stack.pop()
+        if node is None:
+            continue
+        answer[0].append(node.num)
+        stack.append(node.right)
+        stack.append(node.left)
+
+def post_order(root, answer):
+    stack = [(root, False)]
+    while stack:
+        node, visited = stack.pop()
+        if node is None:
+            continue
+        if visited:
+            answer[1].append(node.num)
+        else:
+            stack.append((node, True))
+            stack.append((node.right, False))
+            stack.append((node.left, False))
+
+def solution(nodeinfo):
+    answer = [[], []]
+    root = build_binary_tree(nodeinfo) 
+    pre_order(root, answer)
+    post_order(root, answer)
+    return answer
+
+nodeinfo = [[5, 3], [11, 5], [13, 3], [3, 5], [6,1], [1, 3], [8, 6], [7, 2],
+[2, 2]]
+print(solution(nodeinfo))