python读取邻接矩阵txt文件计算最短路径并输出

要读取邻接矩阵txt文件，你可以使用Python内置的文件读写功能，具体步骤如下：

1. 打开文件并读取邻接矩阵

with open('adj_matrix.txt', 'r') as f:
    adj_matrix = []
    for line in f.readlines():
        row = list(map(int, line.strip().split()))
        adj_matrix.append(row)

其中，`adj_matrix.txt`为邻接矩阵的文本文件名，假设每行用空格分隔，每个元素为整数。

2. 计算最短路径

你可以使用Dijkstra算法或者Floyd算法来计算最短路径。这里以Dijkstra算法为例：

import heapq

def dijkstra(adj_matrix, start):
    n = len(adj_matrix)
    dist = [float('inf')] * n
    dist[start] = 0
    visited = set()
    heap = [(0, start)]
    while heap:
        (d, v) = heapq.heappop(heap)
        if v in visited:
            continue
        visited.add(v)
        for w in range(n):
            if adj_matrix[v][w] != 0 and w not in visited:
                if dist[v] + adj_matrix[v][w] < dist[w]:
                    dist[w] = dist[v] + adj_matrix[v][w]
                    heapq.heappush(heap, (dist[w], w))
    return dist

其中，`adj_matrix`为邻接矩阵，`start`为起点。函数返回一个列表，表示起点到各个点的最短距离。

3. 输出结果

最后，你可以将最短路径输出到文件中，或者直接打印出来。

dist = dijkstra(adj_matrix, 0)
with open('result.txt', 'w') as f:
    for i, d in enumerate(dist):
        f.write(f'{i}: {d}\n')

其中，`result.txt`为结果文件名。这里将起点设为0，将结果输出到文件中。

完整代码：

import heapq

def dijkstra(adj_matrix, start):
    n = len(adj_matrix)
    dist = [float('inf')] * n
    dist[start] = 0
    visited = set()
    heap = [(0, start)]
    while heap:
        (d, v) = heapq.heappop(heap)
        if v in visited:
            continue
        visited.add(v)
        for w in range(n):
            if adj_matrix[v][w] != 0 and w not in visited:
                if dist[v] + adj_matrix[v][w] < dist[w]:
                    dist[w] = dist[v] + adj_matrix[v][w]
                    heapq.heappush(heap, (dist[w], w))
    return dist

with open('adj_matrix.txt', 'r') as f:
    adj_matrix = []
    for line in f.readlines():
        row = list(map(int, line.strip().split()))
        adj_matrix.append(row)

dist = dijkstra(adj_matrix, 0)
with open('result.txt', 'w') as f:
    for i, d in enumerate(dist):
        f.write(f'{i}: {d}\n')