给出贪心法求解tsp问题的代码

以下是使用贪心算法求解TSP问题的Python代码：

import numpy as np

def tsp_greedy(distance_matrix):
    n = len(distance_matrix)
    visited = [False] * n # 记录每个城市是否被访问过
    path = [0] * n # 记录访问路径
    path[0] = start = np.random.randint(0, n) # 随机选择一个起点
    visited[start] = True
    for i in range(1, n):
        # 找到距离当前城市最近的未访问城市
        current_city = path[i-1]
        min_distance = float('inf')
        next_city = -1
        for j in range(n):
            if not visited[j] and distance_matrix[current_city][j] < min_distance:
                min_distance = distance_matrix[current_city][j]
                next_city = j
        visited[next_city] = True
        path[i] = next_city
    # 将最后一个城市与起点相连形成回路
    path[n-1] = start
    # 计算回路的总长度
    total_distance = 0
    for i in range(n):
        total_distance += distance_matrix[path[i-1]][path[i]]
    return path, total_distance

其中，`distance_matrix`是一个二维数组，表示各个城市之间的距离。函数返回值为一个元组，包含访问路径和回路的总长度。