Day 13

13/13-1.py

@@ -0,0 +1,73 @@
+def get_input():
+    with open("13.txt", "r") as f:
+        return [l for l in f.read().splitlines()]
+
+
+def format_reflections(input):
+    reflections = []
+    c = []
+    for i in input:
+        if i == "":
+            reflections.append(c)
+            c = []
+        else:
+            c.append(i)
+    reflections.append(c)
+    return reflections
+
+
+def find_reflection_point(reflection, axis, p):
+    p0, p1 = p
+    if axis == "x":
+        if p1 > len(reflection) - 1:
+            return False
+        to_compare = list(reversed(reflection[: p0 + 1])), reflection[p1:]
+        for i in range(len(min(to_compare))):
+            if to_compare[0][i] != to_compare[1][i]:
+                return False
+
+        return p0 + 1
+
+    if axis == "y":
+        if p1 > len(reflection[0]) - 1:
+            return False
+        to_compare = []
+        i = 0
+        columns = [
+            [reflection[i][j] for i in range(len(reflection))]
+            for j in range(len(reflection[0]))
+        ]
+        to_compare = list(reversed(columns[: p0 + 1])), columns[p1:]
+        for i in range(len(min(to_compare))):
+            if to_compare[0][i] != to_compare[1][i]:
+                return False
+        return p0 + 1
+
+
+def main():
+    input = get_input()
+    reflections = format_reflections(input)
+    sum = 0
+    for r in reflections:
+        reflection_point = False
+        for i in range(0, len(r)):
+            reflection_point = find_reflection_point(r, "x", (i, i + 1))
+            if reflection_point:
+                sum += reflection_point * 100
+                break
+        if not reflection_point:
+            for j in range(0, len(r[0])):
+                reflection_point = find_reflection_point(r, "y", (j, j + 1))
+                if reflection_point:
+                    sum += reflection_point
+                    break
+        if not reflection_point:
+            print("no reflection point found")
+            return False
+    print(sum)
+
+
+main()
+
+
+# 31877

13/13-2.py

@@ -0,0 +1,92 @@
+def get_input():
+    with open("13.txt", "r") as f:
+        return [l for l in f.read().splitlines()]
+
+
+def format_reflections(input):
+    reflections = []
+    c = []
+    for i in input:
+        if i == "":
+            reflections.append(c)
+            c = []
+        else:
+            c.append(i)
+    reflections.append(c)
+    return reflections
+
+
+def find_reflection_point(reflection, axis, p, target_occs=0):
+    p0, p1 = p
+    occurrences = 0
+    if axis == "x":
+        if p1 > len(reflection) - 1:
+            return False
+        to_compare = list(reversed(reflection[: p0 + 1])), reflection[p1:]
+        for i in range(min([len(to_compare[0]), len(to_compare[1])])):
+            if to_compare[0][i] != to_compare[1][i]:
+                for j, char in enumerate(to_compare[0][i]):
+                    if char != to_compare[1][i][j]:
+                        occurrences += 1
+                if occurrences > target_occs:
+                    return False
+
+        return p1 if occurrences == target_occs else False
+
+    if axis == "y":
+        if p1 > len(reflection[0]) - 1:
+            return False
+        to_compare = []
+        columns = [
+            [reflection[i][j] for i in range(len(reflection))]
+            for j in range(len(reflection[0]))
+        ]
+        to_compare = list(reversed(columns[: p0 + 1])), columns[p1:]
+        for i in range(min([len(to_compare[0]), len(to_compare[1])])):
+            if to_compare[0][i] != to_compare[1][i]:
+                for j, char in enumerate(to_compare[0][i]):
+                    if char != to_compare[1][i][j]:
+                        occurrences += 1
+                if occurrences > target_occs:
+                    return False
+        return p1 if occurrences == target_occs else False
+
+
+def summarize_reflection_lines(reflections, target_occurrences):
+    sum = 0    
+    for r in reflections:
+        reflection_point = False
+        for i in range(0, len(r)):
+            reflection_point = find_reflection_point(
+                r, "x", (i, i + 1), target_occs=target_occurrences
+            )
+            if reflection_point:
+                sum += reflection_point * 100
+                break
+        if not reflection_point:
+            for j in range(0, len(r[0])):
+                reflection_point = find_reflection_point(
+                    r, "y", (j, j + 1), target_occs=target_occurrences
+                )
+                if reflection_point:
+                    sum += reflection_point
+                    break
+        if not reflection_point:
+            print("no reflection point found for reflection: ")
+            print(r)
+            return False
+    return sum
+
+
+def main():
+    # set to 0 for part 1, 1 for part 2
+    target_occurrences = 0
+    input = get_input()
+    reflections = format_reflections(input)
+    print(summarize_reflection_lines(reflections, target_occurrences))
+
+
+main()
+
+# 31877 pt 1
+# 42996 pt 2

13/13-test.txt

@@ -0,0 +1,15 @@
+#.##..##.
+..#.##.#.
+##......#
+##......#
+..#.##.#.
+..##..##.
+#.#.##.#.
+
+#...##..#
+#....#..#
+..##..###
+#####.##.
+#####.##.
+..##..###
+#....#..#