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Copy pathmaxPathSum.py
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72 lines (66 loc) · 2.15 KB
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#!/usr/bin/env python
#-*- coding: utf-8 -*-
import os,re,sys,commands,glob,json,collections,random
from random import randint
from LeetCodeUtils import *
class HashWrapper():
def __init__(self, object):
self.object = object
def __hash__(self):
return id(self.object)
def __eq__(self, a):
return self.object == a.object
MIN_INT = -0x80000000
class Solution:
def __init__(self):
self.maxInclusive = {}
pass
# @param root, a tree node
# @return an integer
def maxPathSum(self, root):
self.maxInclusive = {}
return self.maxPathSum2(root)
def maxPathSum2(self, root):
if not root:
return MIN_INT
return max(\
root.val + max(0, self.maxPathSumInclude(root.left))+ max(0, self.maxPathSumInclude(root.right)),\
self.maxPathSum2(root.left), \
self.maxPathSum2(root.right))
def maxPathSumInclude(self, root):
if not root:
return MIN_INT
hash = HashWrapper(root)
if hash in self.maxInclusive:
# print root
return self.maxInclusive[hash]
r = max(root.val, root.val + self.maxPathSumInclude(root.left), \
root.val + self.maxPathSumInclude(root.right))
self.maxInclusive[hash] = r
return r
def solve(root):
return Solution().maxPathSum(root)
pass
def sp(*a):
assert solve(*a[:-1]) == a[-1]
pass
def test1():
sp(TreeNode(1, TreeNode(2, TreeNode(4), TreeNode(5)), TreeNode(3)), 11)
pass
def test():
# sp(None, 0)
sp(TreeNode(-1), -1)
sp(TreeNode(-3), -3)
sp(TreeNode(-3, TreeNode(-1)), -1)
sp(TreeNode(-3, TreeNode(0)), 0)
sp(TreeNode(-3, TreeNode(-4)), -3)
sp(TreeNode(1), 1)
sp(TreeNode(1, TreeNode(2)), 3)
sp(TreeNode(1, TreeNode(2, TreeNode(3))), 6)
sp(TreeNode(1, TreeNode(2), TreeNode(3)), 6)
sp(TreeNode(1, TreeNode(2), TreeNode(-3)), 3)
sp(TreeNode(1, TreeNode(2), TreeNode(-1, TreeNode(4))), 6)
sp(TreeNode(1, TreeNode(2), TreeNode(-1, TreeNode(-4))), 3)
for i in range(100):
solve(RandomTree(10).createTree())
pass