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#!/usr/bin/env python3
# Challenge 056
#
# TASK #2
# Path Sum
# You are given a binary tree and a sum, write a script to find if the tree has
# a path such that adding up all the values along the path equals the given sum.
# Only complete paths (from root to leaf node) may be considered for a sum.
#
# Example
# Given the below binary tree and sum = 22,
#
# 5
# / \
# 4 8
# / / \
# 11 13 9
# / \ \
# 7 2 1
# For the given binary tree, the partial path sum 5 ? 8 ? 9 = 22 is not valid.
#
# The script should return the path 5 ? 4 ? 11 ? 2 whose sum is 22.
import fileinput
import re
import sys
class Node:
def __init__(self, value):
self.value = value
self.left = None
self.right = None
def __repr__(self):
return "Node(value: {}, left: {}, right: {})" \
.format(self.value, self.left, self.right)
def read_input():
lines = []
for line in fileinput.input():
lines.append(line)
return lines
def parse_subtree(lines, row, col):
def ch(row, col):
if row < 0 or row >= len(lines) or \
col < 0 or col >= len(lines[row]):
return ' '
else:
return lines[row][col]
tree = Node(int(lines[row][col]))
if ch(row + 1, col - 1) == '/':
tree.left = parse_subtree(lines, row + 2, col - 2)
if ch(row + 1, col + 1) == '\\':
tree.right = parse_subtree(lines, row + 2, col + 2)
return tree
def parse_tree(lines):
found = re.search(r'^[ ]+\d', lines[0])
col = found.span()[1] - 1
return parse_subtree(lines, 0, col)
def path_sum(path, sum1, tree):
path1 = path+[tree.value]
if not tree.left and not tree.right:
if sum(path1) == sum1:
print(" ".join([str(x) for x in path1]))
else:
if tree.left:
path_sum(path1, sum1, tree.left)
if tree.right:
path_sum(path1, sum1, tree.right)
sum1 = int(sys.argv[1])
sys.argv.pop()
tree = parse_tree(read_input())
path_sum([], sum1, tree)
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