from collections import deque, defaultdict
<p>def topological_sort(edges, n):</p><h1>建图并统计入度</h1><pre class="brush:python;toolbar:false;">graph = defaultdict(list)
indegree = [0] * n

for u, v in edges:
    graph[u].append(v)
    indegree[v] += 1

# 找出入度为 0 的节点
queue = deque([i for i in range(n) if indegree[i] == 0])
result = []

while queue:
    node = queue.popleft()
    result.append(node)

    for neighbor in graph[node]:
        indegree[neighbor] -= 1
        if indegree[neighbor] == 0:
            queue.append(neighbor)

# 如果结果长度等于节点数，说明无环
if len(result) == n:
    return result
else:
    return []  # 存在环，无法拓扑排序

示例：4 个任务，边表示依赖关系

edges = [(0, 1), (0, 2), (1, 2), (2, 3)] n = 4 order = topological_sort(edges, n) print("拓扑排序结果:", order) # 输出: [0, 1, 2, 3]