Bringing some days up to speed after a short break

6/1.py

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+def get_start(grid: list[str]) -> [int, int]:
+    x, y = 0, 0
+    for row, line in enumerate(grid):
+        if '^' in line:
+            y = row
+            break
+    x = grid[y].find('^')
+    return [x, y]
+
+def peek(grid: list[str], x: int, y: int) -> str:
+    try:
+        if y < 0 or x < 0:
+            return ''
+        return grid[y][x]
+    except IndexError:
+        return ''
+
+def rotate(vel: [int, int]) -> [int, int]:
+    # going up? -> go right
+    if vel == [0,-1]:
+        return [1,0]
+    # going right? -> go down
+    elif vel == [1,0]:
+        return [0,1]
+    # going down? -> go left
+    elif vel == [0,1]:
+        return [-1,0]
+    # goign left? -> go up
+    elif vel == [-1,0]:
+        return [0,-1]
+    else:
+        raise ValueError('brother wtf')
+
+def crawl(grid: list[str], x: int, y: int) -> set[(int, int)]:
+    # non -unique set that we'll have to clean up
+    visited = set()
+    visited.add((x,y))
+    vel = [0,-1]
+    while val := peek(grid, x+vel[0], y+vel[1]):
+        # Record where we go
+        print((x,y), 'vel ->', vel)
+        if val == '.' or val == '^':
+            x += vel[0]
+            y += vel[1]
+            visited.add((x,y))
+        # Don't record the walls 
+        if val == '#':
+            vel = rotate(vel)
+    return visited
+    
+if __name__ == '__main__':
+    with open('input.data') as raw:
+        grid = [ line.strip() for line in raw ]
+    start_x, start_y = get_start(grid)
+    print(len(grid), len(grid[0]))
+    places = crawl(grid, start_x, start_y)
+    print(len(places))