Day 13;

Author: sbremer

day13.py

@@ -0,0 +1,113 @@
+import numpy as np
+from collections import namedtuple
+fav_number = 1352
+
+State = namedtuple('State', ['at', 'steps', 'dist'])
+
+
+def is_wall(x, y):
+    i = x*x + 3*x + 2*x*y + y + y*y + fav_number
+    bits = str(bin(i))[2:]
+    return (bits.count('1') % 2) == 1
+
+
+def generate_map(size_x, size_y):
+    wall_map = np.zeros((size_x, size_y))
+
+    for x in range(size_x):
+        for y in range(size_y):
+            if is_wall(x, y):
+                wall_map[x, y] = -1
+
+    return wall_map
+
+
+def valid_pos(at, map_size):
+    if at[0] < 0 or at[1] < 0 or at[0] >= map_size[0] or at[1] >= map_size[1]:
+        return False
+    else:
+        return True
+
+
+def get_dist(v):
+    return np.linalg.norm(v, ord=1)
+
+
+if __name__ == '__main__':
+    start = np.array([1, 1])
+    target = np.array([31, 39])
+
+    map_size = target + 25
+
+    steps = [np.array([0, 1]), np.array([0, -1]), np.array([1, 0]), np.array([-1, 0])]
+
+    wall_map = generate_map(map_size[0], map_size[1])
+
+    states = [State(start, 0, get_dist(target-start))]
+
+    while True:
+        dist_min = np.sum(map_size)
+        i_min = -1
+
+        # Get best current location
+        for i, state in enumerate(states):
+            if state.dist < dist_min:
+                dist_min = state.dist
+                i_min = i
+
+        state = states[i_min]
+        del states[i_min]
+        wall_map[state.at[0], state.at[1]] = 1
+
+        if dist_min == 0:
+            break
+
+        # Generate new steps
+        states_new = []
+
+        for step in steps:
+            new_pos = state.at + step
+
+            if not valid_pos(new_pos, map_size) or wall_map[new_pos[0], new_pos[1]] != 0:
+                continue
+
+            new_state = State(new_pos, state.steps + 1, get_dist(target-new_pos))
+            states_new.append(new_state)
+
+        states.extend(states_new)
+
+    print('Minimum distance to target: {}'.format(state.steps))
+
+    # Reset map
+    wall_map = generate_map(map_size[0], map_size[1])
+
+    positions = [start]
+    wall_map[start[0], start[1]] = 1
+    total_fields = 1
+
+    for a in range(50):
+
+        positions_new = []
+
+        for position in positions:
+
+            for step in steps:
+                position_new = position + step
+
+                if not valid_pos(position_new, map_size) or wall_map[position_new[0], position_new[1]] != 0:
+                    continue
+
+                wall_map[position_new[0], position_new[1]] = 1
+                positions_new.append(position_new)
+                total_fields += 1
+
+        positions = positions_new
+
+    print('Total positions accessible in 50 steps: {}'.format(total_fields))
+
+
+
+
+
+
+