Buggy python submission (verdict: Runtime Error):
import sys
if __name__ == "__main__":
    N,X = map(int, input().split())
    res = 2 * N - 1
    if (X == 1 or X == 2 * N - 1):
        print ("No")
        sys.exit()
    result = [0] * res
    left = X - 1
    result[N-1] = X
    right = X + 1
    left_idx = N - 2
    right_idx = N

    cnt = 0
    while (left > 0 and right < 2 * N):
        if (cnt % 2 == 0):
            result[left_idx] = left
            result[right_idx] = right
        else:
            result[left_idx] = right
            result[right_idx] = left

        left_idx -= 1
        left -= 1

        right_idx += 1
        right += 1

        cnt += 1
    if (left > 0):
        for x in range(left_idx, -1, -1):
            res[x] = left
            left -= 1
        for x in range(right_idx, 2 * N):
            res[x] = left
            left -= 1
    if (right < 2 * N):
        for x in range(left_idx, -1, -1):
            res[x] = right
            right += 1
        for x in range(right_idx, 2 * N):
            res[x] = right
            right += 1

    print ("Yes")
    for x in result:
        print (x)


Fixed submission:

import sys
if __name__ == "__main__":

	N,X = map(int, input().split())
	res = 2 * N - 1
	if (X == 1 or X == 2 * N - 1):
		print ("No")
		sys.exit()
	result = [0] * res
	left = X - 1
	result[N-1] = X
	right = X + 1
	left_idx = N - 2
	right_idx = N

	cnt = 0
	while (left > 0 and right < 2 * N):
		if (cnt % 2 == 0):
			result[left_idx] = left
			result[right_idx] = right
		else:
			result[left_idx] = right
			result[right_idx] = left

		left_idx -= 1
		left -= 1

		right_idx += 1
		right += 1

		cnt += 1
	if (left > 0):
		for x in range(left_idx, -1, -1):
			result[x] = left
			left -= 1
		for x in range(right_idx, 2 * N-1):
			result[x] = left
			left -= 1
	if (right < 2 * N):
		for x in range(left_idx, -1, -1):
			result[x] = right
			right += 1
		for x in range(right_idx, 2 * N-1):
			result[x] = right
			right += 1

	print ("Yes")
	for x in result:
		print (x)

Buggy python submission (verdict: Runtime Error):
import sys
if __name__ == "__main__":
    N,X = map(int, input().split())
    res = 2 * N - 1
    if (X != N - 1 and X != N and X != N + 1):
        print ("No")
        sys.exit()
    result = [0] * res
    left = X - 1
    result[N-1] = X
    right = X + 1
    left_idx = N - 2
    right_idx = N

    cnt = 0
    while (left > 0 and right < 2 * N):
        if (cnt % 2 == 0):
            result[left_idx] = left
            result[right_idx] = right
        else:
            result[left_idx] = right
            result[right_idx] = left

        left_idx -= 1
        left -= 1

        right_idx += 1
        right += 1

        cnt += 1
    if (left > 0):
        for x in range(left_idx, -1, -1):
            res[x] = left
            left -= 1
        for x in range(right_idx, 2 * N):
            res[x] = left
            left -= 1
    if (right < 2 * N):
        for x in range(left_idx, -1, -1):
            res[x] = right
            right += 1
        for x in range(right_idx, 2 * N):
            res[x] = right
            right += 1

    print ("Yes")
    for x in result:
        print (x)


Fixed submission:

import sys
if __name__ == "__main__":

	N,X = map(int, input().split())
	res = 2 * N - 1
	if (X == 1 or X == 2 * N - 1):
		print ("No")
		sys.exit()
	result = [0] * res
	left = X - 1
	result[N-1] = X
	right = X + 1
	left_idx = N - 2
	right_idx = N

	cnt = 0
	while (left > 0 and right < 2 * N):
		if (cnt % 2 == 0):
			result[left_idx] = left
			result[right_idx] = right
		else:
			result[left_idx] = right
			result[right_idx] = left

		left_idx -= 1
		left -= 1

		right_idx += 1
		right += 1

		cnt += 1
	if (left > 0):
		for x in range(left_idx, -1, -1):
			result[x] = left
			left -= 1
		for x in range(right_idx, 2 * N-1):
			result[x] = left
			left -= 1
	if (right < 2 * N):
		for x in range(left_idx, -1, -1):
			result[x] = right
			right += 1
		for x in range(right_idx, 2 * N-1):
			result[x] = right
			right += 1

	print ("Yes")
	for x in result:
		print (x)