1 files changed, 52 insertions, 0 deletions
diff --git a/2021/day21/21.py b/2021/day21/21.py
new file mode 100644
index 0000000..8cd8307
--- /dev/null
+++ b/2021/day21/21.py
@@ -0,0 +1,52 @@
+
+die_val = 1
+rolls = 0
+def roll():
+    global die_val, rolls
+    x = die_val
+
+    die_val += 1
+    if die_val > 100:
+        die_val = 1
+
+    rolls += 1
+
+    return x
+
+
+class Player:
+    def __init__(self, pos):
+        self.pos = pos
+        self.score = 0
+
+    def move(self, roll):
+        self.pos += roll
+        while self.pos > 10:
+            self.pos -= 10
+
+    def take_turn(self):
+        r = sum([roll() for _ in range(0, 3)])
+        self.move(r)
+        self.score += self.pos
+
+    def __str__(self):
+        return "<Player pos=%d score=%d>" % (self.pos, self.score)
+
+inp = open("./input").read().split("\n")
+p1_start = int(inp[0].split(": ")[1])
+p2_start = int(inp[1].split(": ")[1])
+
+p1 = Player(p1_start)
+p2 = Player(p2_start)
+turn = p1
+while p1.score < 1000 and p2.score < 1000:
+    turn.take_turn()
+    if turn == p1:
+        turn = p2
+    else:
+        turn = p1
+
+ans = p1.score * rolls
+if p1.score >= 1000:
+    ans = p2.score * rolls
+print("Part 1: %d" % ans)