1 files changed, 87 insertions, 0 deletions
diff --git a/2022/day21.py b/2022/day21.py
new file mode 100755
index 0000000..a730104
--- /dev/null
+++ b/2022/day21.py
@@ -0,0 +1,87 @@
+#!/usr/bin/env python3
+
+# import numpy as np
+from functools import reduce
+from re import findall
+from copy import deepcopy
+import sys
+
+# filename = "in/day21.ref"
+filename = "in/day21.pzl"
+data = open(filename).read()
+lines = [line for line in data.rstrip('\n').split('\n')]
+
+M = dict()
+for line in lines:
+    s = line.split(' ')
+    if len(s) == 2:
+        M[s[0].strip(':')] = int(s[1])
+    elif len(s) == 4:
+        M[s[0].strip(':')] = (s[1], s[3], s[2])
+    else:
+        print('error parsing')
+# print(M)
+# print(M['root'])
+
+
+# part1
+def op1(node):
+    if type(M[node]) == int:
+        return M[node]
+    else:
+        n1 = op1(M[node][0])
+        n2 = op1(M[node][1])
+        if M[node][2] == '+':
+            return n1 + n2
+        elif M[node][2] == '-':
+            return n1 - n2
+        elif M[node][2] == '*':
+            return n1 * n2
+        elif M[node][2] == '/':
+            # int divide
+            return n1 // n2
+
+res1 = op1('root')
+
+
+# part2
+def op2(node, guess):
+    if node == 'root':
+        n1 = op2(M[node][0], guess)
+        n2 = op2(M[node][1], guess)
+        return n1, n2
+    elif node == 'humn':
+        return guess
+    elif type(M[node]) == int:
+        return M[node]
+    else:
+        n1 = op2(M[node][0], guess)
+        n2 = op2(M[node][1], guess)
+        if M[node][2] == '+':
+            return n1 + n2
+        elif M[node][2] == '-':
+            return n1 - n2
+        elif M[node][2] == '*':
+            return n1 * n2
+        elif M[node][2] == '/':
+            # float divide
+            return n1 / n2
+
+def bisect(start, stop):
+    for _ in range(200):
+        guess = (start + stop) // 2
+        n1, n2 = op2('root', guess)
+        # print(guess, n1, n2)
+        if n1 == n2:
+            return guess
+        elif n1 > n2:
+            start = guess
+        else:
+            stop = guess
+
+res2 = bisect(0, 50000000000000)
+
+
+print('res1:', res1)
+print('res2:', res2)
+