aoc22/day9-1.py

def expandGrid(direct):
    if direct == "U":
        gridVisited.insert(0, [])
        for _ in range(len(gridVisited[1])):
            gridVisited[0].append('.')
        posHead[0] = posHead[0] + 1
        posTail[0] = posTail[0] + 1
    elif direct == "R":
        for i in range(len(gridVisited)):
            gridVisited[i].append('.')
    elif direct == "D":
        gridVisited.append([])
        tempx = len(gridVisited) - 1
        for _ in range(len(gridVisited[0])):
            gridVisited[tempx].append('.')
    elif direct == "L":
        for i in range(len(gridVisited)):
            gridVisited[i].insert(0, '.')
        posHead[1] = posHead[1] + 1
        posTail[1] = posTail[1] + 1

def checkDist():
    tempa = posHead[1] - posTail[1]
    tempb = posHead[0] - posTail[0]
    tempc = tempa + tempb
    if posHead[0] == posTail[0]:
        if not(tempa == 1 or tempa == -1):
            if tempa > 0:
                posTail[1] += 1
            elif tempa < 0:
                posTail[1] -= 1
    elif posHead[1] == posTail[1]:
        tempa = posHead[0] - posTail[0]
        if not(tempb == 1 or tempb == -1):
            if tempb > 0:
                posTail[0] += 1
            elif tempb < 0:
                posTail[0] -= 1
    elif (tempc == -1 or tempc == 1)  and tempb < 0:
        posTail[0] -= 1
        posTail[1] += 1
    elif tempc == 3:
        posTail[0] += 1
        posTail[1] += 1
    elif (tempc == -1 or tempc == 1)  and tempb > 0:
        posTail[0] += 1
        posTail[1] -= 1
    elif tempc == -3:
        posTail[0] -= 1
        posTail[1] -= 1
    gridVisited[posTail[0]][posTail[1]] = '#'

gridVisited =[['#']]
posHead = [0, 0]
posTail = [0, 0]

with open('input9.txt','r') as f:
    inp = f.read().splitlines(keepends=False)

direction = []
distance = []

for i in inp:
    tempa, tempb = i.split(' ')
    direction.append(tempa)
    distance.append(int(tempb))

for x in range(len(direction)):
    if direction[x] == 'U':
        for y in range(distance[x]):
            if posHead[0] == 0:
                expandGrid("U")
            posHead[0] -= 1
            checkDist()
    elif direction[x] == 'R':
        for y in range(distance[x]):
            if posHead[1] == len(gridVisited[0])-1:
                expandGrid("R")
            posHead[1] += 1
            checkDist()
    elif direction[x] == 'D':
        for y in range(distance[x]):
            if posHead[0] == len(gridVisited) - 1:
                expandGrid("D")
            posHead[0] += 1
            checkDist()
    elif direction[x] == 'L':
        for y in range(distance[x]):
            if posHead[1] == 0:
                expandGrid("L")
            posHead[1] -= 1
            checkDist()

visited = 0

for i in gridVisited:
    for x in i:
        if x == '#':
            visited += 1

print(visited)