二叉树相关 124题 二叉树中的最大路径和

Author: imbaliking

new_issue/binary-tree-maximum-path-sum.py

@@ -0,0 +1,25 @@
+def maxPathSum(root):
+    """
+    :type root: TreeNode
+    :rtype: int
+    """
+    max_sum = -1001
+
+    def division(node, max_sum):
+        current_max = node.val
+        left_max_sum = -1001
+        right_max_sum = -1001
+        left_max_path = 0
+        right_max_path = 0
+        if node.left is not None:
+            left_max_sum, left_max_path = division(node.left, max_sum)
+
+        if node.right is not None:
+            right_max_sum, right_max_path = division(node.right, max_sum)
+
+        max_path = max(current_max, current_max + left_max_path, current_max + right_max_path)
+        max_sum = max(max_sum, max_path, current_max + left_max_path + right_max_path, left_max_sum, right_max_sum)
+        return max_sum, max_path
+
+    max_sum, max_path = division(root, max_sum)
+    return max(max_sum, max_path)