edmonds-karp算法的代码
时间: 2024-04-22 18:24:00 浏览: 60
edmonds-karp:Edmonds-Karp最大流算法的C ++实现
下面是一个简单的Python实现Edmonds-Karp算法的代码示例:
```python
from collections import deque
def bfs(graph, residual_capacity, parent, source, sink):
visited = [False] * len(graph)
queue = deque()
queue.append(source)
visited[source] = True
while queue:
u = queue.popleft()
for v in range(len(graph)):
if not visited[v] and residual_capacity[u][v] > 0:
queue.append(v)
visited[v] = True
parent[v] = u
if v == sink:
return True
return False
def edmonds_karp(graph, source, sink):
n = len(graph)
residual_capacity = [[0] * n for _ in range(n)]
parent = [-1] * n
max_flow = 0
while bfs(graph, residual_capacity, parent, source, sink):
path_flow = float('inf')
s = sink
while s != source:
path_flow = min(path_flow, residual_capacity[parent[s]][s])
s = parent[s]
max_flow += path_flow
v = sink
while v != source:
u = parent[v]
residual_capacity[u][v] -= path_flow
residual_capacity[v][u] += path_flow
v = parent[v]
return max_flow
# 测试代码
graph = [
[0, 16, 13, 0, 0, 0],
[0, 0, 10, 12, 0, 0],
[0, 4, 0, 0, 14, 0],
[0, 0, 9, 0, 0, 20],
[0, 0, 0, 7, 0, 4],
[0, 0, 0, 0, 0, 0]
]
source = 0
sink = 5
max_flow = edmonds_karp(graph, source, sink)
print("最大流量为:", max_flow)
```
这段代码中,我们使用了邻接矩阵表示图,并使用一个二维数组`residual_capacity`来存储残留容量。`bfs`函数实现了广度优先搜索来寻找增广路径,并更新了`parent`数组。`edmonds_karp`函数则是主要的算法部分,通过不断寻找增广路径来更新流量和残留容量,直到没有增广路径为止。最后,我们使用测试数据进行了测试,并输出最大流量的结果。
请注意,这只是一个简单的示例代码,实际应用中可能需要根据具体情况进行相应的调整和优化。
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