“Algoritmo de Python Warshall stackoverflow” Código de respuesta

Algoritmo de Python Warshall stackoverflow

def warshall(a):
    assert (len(row) == len(a) for row in a)
    n = len(a)
    for k in range(n):
        for i in range(n):
            for j in range(n):
                a[i][j] = a[i][j] or (a[i][k] and a[k][j])
    return a