extra/bringing-a-gun-to-a-trainer-fight/solution.py

@@ -1,2 +1,62 @@
-def​ ​solution(dimensions,​ ​your_position,​ ​trainer_position,​ ​distance):
-​ ​​ ​​ ​​ ​#Your​ ​code​ ​here
+def solution(dimentions, your_position, trainer_position, distance):
+    direction_target_map = {}
+    for reflected_position, is_trainer in generate_relected_positions(dimentions, your_position, trainer_position, distance):
+        direction = reduce_direction((reflected_position[0] - your_position[0], reflected_position[1] - your_position[1]))
+        travel = travel_distance(your_position, reflected_position)
+        if (direction in direction_target_map):
+            if travel < direction_target_map[direction][0]:
+                direction_target_map[direction] = (travel, is_trainer)
+        else:
+            direction_target_map[direction] = (travel, is_trainer)
+    return len([k for k, (d, is_trainer) in direction_target_map.items() if is_trainer])
+
+def generate_relected_positions(dimentions, your_position, trainer_position, distance):
+    room_width, room_height = dimentions
+    x_range = distance // room_width + 1
+    y_range = distance // room_height + 1
+    for room_x in range(-x_range, x_range):
+        for room_y in range(-y_range, y_range):
+            x_reflected = room_x % 2 == 1
+            y_reflected = room_y % 2 == 1
+            x_base, y_base = room_x*room_width, room_y*room_height
+            your_x_offset, your_y_offset = your_position
+            trainer_x_offset, trainer_y_offset = trainer_position
+            if (x_reflected):
+                your_x_offset = room_width - your_x_offset
+                trainer_x_offset = room_width - trainer_x_offset
+            if (y_reflected):
+                your_y_offset = room_height - your_y_offset
+                trainer_y_offset = room_height - trainer_y_offset
+            reflected_your_position = x_base + your_x_offset, y_base + your_y_offset
+            reflected_trainer_position = x_base + trainer_x_offset, y_base + trainer_y_offset
+            reflected_your_distance = travel_distance(your_position, reflected_your_position)
+            reflected_trainer_distance = travel_distance(your_position, reflected_trainer_position)
+            if reflected_your_distance <= distance:
+                yield reflected_your_position, False
+            if reflected_trainer_distance <= distance:
+                yield reflected_trainer_position, True
+
+def abs_gcd(x, y):
+    m, n = abs(x), abs(y)
+    while n != 0:
+        t = m % n
+        m, n = n, t
+    return abs(m)
+
+def reduce_direction(direction):
+    if direction[0] == 0 or direction[1] == 0:
+        return direction
+    gcd = abs_gcd(direction[0], direction[1])
+    return direction[0]/gcd, direction[1]/gcd
+
+def travel_distance(origin, target):
+    return ((target[0] - origin[0])**2 + (target[1] - origin[1])**2) ** 0.5
+
+tests = [
+    (([3, 2], [1, 1], [2, 1], 4), 7),
+    (([300,275], [150,150], [185,100], 500), 9)
+]
+
+for i, o in tests:
+    result = solution(*i)
+    print(i, result == o, result, o)