python 实现将带权图的领接矩阵转换成邻接表，和将邻接表转换成邻接矩阵 及测试用例

以下是将带权图的领接矩阵转换成邻接表的 Python 代码和测试用例：

def matrix_to_list(matrix):
    n = len(matrix)
    graph = {}
    for i in range(n):
        for j in range(n):
            if matrix[i][j] != 0:
                if i not in graph:
                    graph[i] = []
                graph[i].append((j, matrix[i][j]))
    return graph

# 测试用例
matrix = [
    [0, 2, 3, 0],
    [2, 0, 4, 1],
    [3, 4, 0, 5],
    [0, 1, 5, 0]
]
graph = matrix_to_list(matrix)
print(graph)  # 输出：{0: [(1, 2), (2, 3)], 1: [(0, 2), (2, 4), (3, 1)], 2: [(0, 3), (1, 4), (3, 5)], 3: [(1, 1), (2, 5)]}

以下是将邻接表转换成邻接矩阵的 Python 代码和测试用例：

def list_to_matrix(graph, directed=False):
    n = len(graph)
    matrix = [[0] * n for _ in range(n)]
    for node in graph:
        for neighbor, weight in graph[node]:
            matrix[node][neighbor] = weight
            if not directed:
                matrix[neighbor][node] = weight
    return matrix

# 测试用例
graph = {
    0: [(1, 2), (2, 3)],
    1: [(0, 2), (2, 4), (3, 1)],
    2: [(0, 3), (1, 4), (3, 5)],
    3: [(1, 1), (2, 5)]
}
matrix = list_to_matrix(graph)
print(matrix)  # 输出：[[0, 2, 3, 0], [2, 0, 4, 1], [3, 4, 0, 5], [0, 1, 5, 0]]

注意，测试用例中的带权图是一个无向图，如果是有向图需要将 `directed` 参数设置为 `True`。