Solve day 18 and 19 2017.

2017/d19.py

@@ -0,0 +1,50 @@
+from lib import Grid2D, LETTERS_UPPER, add2, sub2
+
+
+def part_1(data):
+    g = Grid2D(data)
+    g.print()
+
+    current = None
+    for c in range(g.n_cols):
+        if g[(0, c)] == "|":
+            current = (0, c)
+
+    current_dir = Grid2D.S
+    letters = ""
+    done = False
+    steps = 0
+
+    while not done:
+        while g[current] != " ":
+            current = add2(current, current_dir)
+            steps += 1
+            if g[current] in LETTERS_UPPER:
+                letter = g[current]
+                if letter in letters:
+                    done = True
+                    break
+                letters += letter
+
+            if g[current] == "+":
+                break
+
+        next_field = None
+        for nb in g.neighbors_ort(current):
+            if nb != sub2(current, current_dir) and (g[nb] in "-|" or g[nb] in LETTERS_UPPER):
+                next_field = nb
+        if next_field is None:
+            done = True
+        else:
+            current_dir = sub2(next_field, current)
+    print(letters)
+    print(steps)
+
+
+def main():
+    data = open(0).read()
+    part_1(data)
+
+
+if __name__ == "__main__":
+    main()