Python-сообщество

 import random
import pprint
def graph_generator(n, mean_degree, max_weight):
    if mean_degree < 2 * (n - 1) / n:
        mean_degree = 2 * (n - 1) / n
    if mean_degree > n - 1:
        mean_degree = (n - 1)
    num_of_edges = int(mean_degree * n / 2)
    W = []
    for i in range(n):
        W.append(['-'] * n)
        W[i][i] = 0
    stack = []
    for i in range(n):
        stack.append(i)
    random.shuffle(stack)
    while stack:
        first = stack.pop()
        if stack:
            second = random.choice(stack)
            W[first][second] = W[second][first] = random.randint(1, max_weight)
    edges_not_tree = num_of_edges - (n - 1)
    for _ in range(edges_not_tree):
        first = random.randint(0, n - 1)
        second = random.randint(0, n - 1)
    W[first][second] = W[second][first] = random.randint(1, max_weight)
    return W