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#!/usr/bin/env python
# Challenge 093
#
# TASK #2 > Sum Path
# Submitted by: Mohammad S Anwar
# You are given binary tree containing numbers 0-9 only.
#
# Write a script to sum all possible paths from root to leaf.
#
# Example 1:
# Input:
# 1
# /
# 2
# / \
# 3 4
#
# Output: 13
# as sum two paths (1->2->3) and (1->2->4)
# Example 2:
# Input:
# 1
# / \
# 2 3
# / / \
# 4 5 6
#
# Output: 26
# as sum three paths (1->2->4), (1->3->5) and (1->3->6)
import fileinput
import re
class Node:
"""one node of a tree"""
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():
"""read standard input into array"""
lines = []
for line in fileinput.input():
lines.append(line)
return lines
def parse(lines):
"""parse a tree, return root Node"""
def parse_subtree(lines, row, col):
"""parse a sub-tree, return root Node"""
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
found = re.search("^[ ]+\d", lines[0])
col = found.span()[1] - 1
return parse_subtree(lines, 0, col)
def add_tree_paths(tree):
"""sum all sub-tree paths"""
def add_subtree_paths(node, cur_len, total_len):
"""return the subtree path len"""
cur_len += node.value
if node.left:
total_len = add_subtree_paths(node.left, cur_len, total_len)
if node.right:
total_len = add_subtree_paths(node.right, cur_len, total_len)
if not node.left and not node.right: # at a leaf
total_len += cur_len
return total_len
return add_subtree_paths(tree, 0, 0)
def solve():
lines = read_input()
tree = parse(lines)
print(add_tree_paths(tree))
solve()
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