Day3AdventCode | Python Fiddle

p_input = 312051

total, level = 1, 1

while total < p_input:
    level += 2
    total = total + level*4 - 4 # or the easy (not my) way: total = level ** 2

offset = total - p_input
steps = offset % (level - 1)

print (level - 1) / 2 + abs((level / 2) - steps)

# x, y, value
values = [(0, 0, 1)]

directions = [(0, 1), (-1, 0), (0, -1), (1, 0)]

level = 1
x, y = 0, 0

terminate = False

while not terminate:

for direction in range(4):

if terminate:
            break

dirX, dirY = directions[direction]

if direction == 0:
            moveN = level - 2
        elif direction in [1, 2]:
            moveN = level - 1
        else:
             moveN = level

for _ in range(moveN):

x += dirX
            y += dirY

new = sum([k[2] for k in values if abs(x-k[0]) <= 1 and abs(y-k[1]) <= 1])
            values.append((x, y, new))

if new >= p_input:
                print new

terminate = True
                break

level += 2

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