DFS vs. Kruskal runtime (maze generation) - python-3.x

Question

I have written two algorithms for creating unique mazes, one of them using depth-first-search (DFS) and the other using Kruskal's. The DFS algorithm performs as expected, however Kruskal's algorithm runs marginally slower than DFS and I do not know why.
I had written Kruskal's algorithm in Python.
I suspect the random.choice() function seems to be the underlying problem. The difference in runtime becomes noticeable when (r, c) > 30.
Here is the code for Kruskal's algorithm:
# Create a list of all possible edges
def create_edges(r, c):
edges = []
for y in range(r):
for x in range(c):
i = (y, x)
for d in ((0, 1), (0, -1), (1, 0), (-1, 0)):
p = tuple(map(sum, zip(d, i)))
py = p[0]
px = p[1]
if px in range(c) and py in range(r):
edges.append([i, p])
return edges
def kruskal(r, c, sz):
path = []
# Create a list of parent root nodes
roots = {(y, x) : [(y, x)] for y in range(r) for x in range(c)}
edges = create_edges(r, c)
while edges:
# Choose a random edge
edge = random.choice(edges)
parent = edge[0]
child = edge[1]
parent_set = get_set(roots, parent)
child_set = get_set(roots, child)
# Check if the parent / child are already in the same set
if parent_set == child_set:
rev_edge = edge.reverse()
if rev_edge in edges:
edges.remove(rev_edge)
edges.remove(edge)
continue
roots[parent_set] += roots[child_set]
roots.pop(child_set)
path.extend((parent, child))
rev_edge = edge.reverse()
if rev_edge in edges:
edges.remove(rev_edge)
edges.remove(edge)
return path
def get_set(roots, member):
s = None
for parent, children in roots.items():
if member in children:
s = parent
return s
def create_maze(t, r, c, sz):
maze = [['|_' for _ in range(c)] for _ in range(r)]
for cell in maze: cell.append('| ')
wd = {'DOWN' : ( 1, 0),
'UP' : (-1, 0),
'LEFT' : ( 0, -1),
'RIGHT': ( 0, 1)}
for n in range(len(t) - 1):
a = n
b = n + 1
p1 = t[a]
p2 = t[b]
ay, ax = p1[0], p1[1]
by, bx = p2[0], p2[1]
w = tuple(numpy.array(p2) - numpy.array(p1))
if w in wd.values():
k = list(wd.keys())[list(wd.values()).index(w)]
if k == 'DOWN': maze[ay][ax] = maze[ay][ax].replace('_', ' ')
if k == 'UP': maze[by][bx] = maze[by][bx].replace('_', ' ')
if k == 'LEFT': maze[ay][ax] = maze[ay][ax].replace('|', ' ')
if k == 'RIGHT': maze[by][bx] = maze[by][bx].replace('|', ' ')
return maze
def print_maze(maze, r, c, delay = 0):
s, l = min((r, c)), max((r, c))
a = 1 / (4 * r * c)
e = (1 / (s * l)) ** 2
delay = (a * 2.718 ** (-1 * e)) ** 0.5
time.sleep(delay)
print(' _' * c)
for iy in range(r):
for ix in range(c + 1):
print(maze[iy][ix], end = '')
print('')
print('')
def main():
r = 30
c = 30
sz = r * c
path = kruskal(r, c, sz)
maze = create_maze(path, r, c, sz)
print_maze(maze, r, c)
if __name__ == "__main__":
main()