请求将TXT图结构输入转换为邻接表格式并补全无子节点项

Problem Overview #

I need to convert graph structure input from a TXT file into a specified adjacency list format. The rules are as follows:

• First line values: Two numbers A and B where:
  • A: Total number of unique numbered nodes in the file
  • B: Total number of connections between nodes (e.g., pairs like 1-0, 0-1 count as separate connections)
• Remaining lines: Each line represents a direct connection between two nodes.

Expected Conversion Examples #

Example 1 (No Outgoing Edges for Some Nodes)

Input:

3 2
0 1
1 2

Output:

{ 0 : [1], 1 : [2], 2 : [], }

Note: Nodes with no outgoing connections must have an empty array [] as their value.

Example 2 (Cyclic Graph)

Input:

2 2
1 0
0 1

Output:

{ 1 : [0], 0 : [1], }

Current JavaScript Code Issue #

My existing JavaScript code can't complete the conversion properly, and it doesn't add empty arrays for nodes with no outgoing connections:

const USER_INPUT = "2 2\n1 0\n0 1"; function getInputLines(input) { const LINE_SEPARATOR = '\n'; return input.split(LINE_SEPARATOR); } function getLineElements(line) { const ELEM_SEPARATOR = ' '; return line.split(ELEM_SEPARATOR) }

Reference Python Code for Cycle Detection #

Below is a Python snippet to detect cycles in a graph, provided for reference:

def cycle_exists(G): color = { u : "white" for u in G } found_cycle = [False] for u in G: if color[u] == "white": dfs_visit(G, u, color, found_cycle) if found_cycle[0]: break return found_cycle[0] def dfs_visit(G, u, color, found_cycle): if found_cycle[0]: return color[u] = "gray" for v in G[u]: if color[v] == "gray": found_cycle[0] = True return if color[v] == "white": dfs_visit(G, v, color, found_cycle) color[u] = "black"

Code Input Example:

graph = { 1 : [0], 0 : [] }

Call Example:

>>> cycle_exists(graph)
>>> False

Content of this question originates from Stack Exchange, asked by user piotrek_k