From c305a3bfcaf6027caf286ce0bd611372d118c43b Mon Sep 17 00:00:00 2001
From: Ben Charlton <ben@spod.cx>
Date: Tue, 22 Dec 2020 20:01:31 +0000
Subject: [PATCH] day 18

---
 18/18-1.py | 57 +++++++++++++++++++++++++++++++++++++++++++++++++
 18/18-2.py | 62 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 119 insertions(+)
 create mode 100644 18/18-1.py
 create mode 100644 18/18-2.py

diff --git a/18/18-1.py b/18/18-1.py
new file mode 100644
index 0000000..2c4e5e5
--- /dev/null
+++ b/18/18-1.py
@@ -0,0 +1,57 @@
+#!/usr/bin/python3
+
+import sys, re
+
+def find_paren(items):
+    if ')' not in items:
+        return None
+    close = items.index(')')
+    for x in range(close, -1, -1):
+        #print (x,items[x])
+        if items[x] == '(':
+            return(x, close)
+
+def do(op, a, b):
+    if op == '+':
+        return a+b
+    elif op == '-':
+        return a-b
+    elif op == '*':
+        return a*b
+    elif op == '/':
+        return a/b
+
+def solve(nums):
+    items = nums.split(' ')
+    total = None
+    op = ''
+    for n in items:
+        if n == '*' or n == '+' or n == '-' or n == '/':
+            op = n
+        else:
+            if total is None:
+                total = int(n)
+            else:
+                total = do(op, total, int(n))
+    return total
+
+
+def process(items):
+
+    p = find_paren(items)
+    while p is not None:
+        before = p[0]
+        after = p[1]
+
+        nitems = items[:before] + str(solve(items[before+1:after])) + items[after+1:]
+        items = nitems
+        p = find_paren(items)
+    return(solve(items))
+
+all = []
+for line in sys.stdin:
+    line = line.rstrip()
+    print(line)
+    all.append(process(line))
+
+print(sum(all))
\ No newline at end of file
diff --git a/18/18-2.py b/18/18-2.py
new file mode 100644
index 0000000..df84953
--- /dev/null
+++ b/18/18-2.py
@@ -0,0 +1,62 @@
+#!/usr/bin/python3
+
+import sys, re
+
+def find_paren(items):
+    if ')' not in items:
+        return None
+    close = items.index(')')
+    for x in range(close, -1, -1):
+        #print (x,items[x])
+        if items[x] == '(':
+            return(x, close)
+
+def do(op, a, b):
+    if op == '+':
+        return a+b
+    elif op == '-':
+        return a-b
+    elif op == '*':
+        return a*b
+    elif op == '/':
+        return a/b
+
+def solve(nums):
+    items = nums.split(' ')
+    total = None
+    op = ''
+    for n in items:
+        if n == '*' or n == '+' or n == '-' or n == '/':
+            op = n
+        else:
+            if total is None:
+                total = int(n)
+            else:
+                total = do(op, total, int(n))
+
+    return total
+
+
+def process(items):
+    items =re.sub('(\d+ \+ \d+)', '(\\1)', items)
+    print(items)
+    p = find_paren(items)
+    while p is not None:
+        before = p[0]
+        after = p[1]
+        nitems = items[:before] + str(solve(items[before+1:after])) + items[after+1:]
+        items = nitems
+        
+        items =re.sub('(\d+ \+ \d+)', '(\\1)', items)
+        p = find_paren(items)
+    return(solve(items))
+
+all = []
+for line in sys.stdin:
+    line = line.rstrip()
+    print(line)
+    res = process(line)
+    print(res)
+    all.append(res)
+
+print(sum(all))
\ No newline at end of file