Depth First Search in Python

Published on 12 November 2021 (Updated: 12 November 2021)

Welcome to the Depth First Search in Python page! Here, you'll find the source code for this program as well as a description of how the program works.

Current Solution

import sys

def get_input(argv):
    error_message = 'Usage: please provide a tree in an adjacency matrix form ("0, 1, 1, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0") together with a list of vertex values ("1, 3, 5, 2, 4") and the integer to find ("4")'

    # check input
    if len(argv) != 3:
    tree, vertex_values, target = argv
    if not tree or not vertex_values or not target:

    # convert strings to lists
    tree = list(map(int, tree.split(', ')))
    vertex_values = list(map(int, vertex_values.split(', ')))
    tree = [tree[i: i + len(vertex_values)] for i in range(0, len(tree), len(vertex_values))]
    target = int(target)

    return tree, vertex_values, target

class TreeNode:
    def __init__(self, val):
        self.val = val
        self.connected = []

def create_tree(tree, vertex_values):
    nodes = {value: TreeNode(value) for value in vertex_values}
    for i, row in enumerate(tree):
        node = nodes[vertex_values[i]]
        for j, is_connected in enumerate(row):
            if j <= i:
            if is_connected:
    head = nodes[vertex_values[0]]
    return head

def depth_first_search(node, target):
    if node.val == target:
        return True
    for connected_node in node.connected:
        if depth_first_search(connected_node, target):
            return True
    return False

def main():
    tree, vertex_values, target = get_input(sys.argv[1:])
    tree_head = create_tree(tree, vertex_values)
    if depth_first_search(tree_head, target):

if __name__ == '__main__':

Depth First Search in Python was written by:

If you see anything you'd like to change or update, please consider contributing.

How to Implement the Solution

No 'How to Implement the Solution' section available. Please consider contributing.

How to Run the Solution

No 'How to Run the Solution' section available. Please consider contributing.