Day 16

Author: Chris Poch

16.py

@@ -0,0 +1,145 @@
+import os
+from collections import defaultdict
+import itertools
+
+debug = False
+fileName = ""
+try:
+    fileName = sys.argv[1]
+    if len(fileName) < 1:
+        fileName = "16.txt"
+except:
+    fileName = "16.txt"
+if debug:
+    print(fileName)
+
+fields = {}
+invalidValues = {}
+
+def validateFields(values, min1, max1, min2, max2):
+    valid = True
+    for value in values:
+        if (value < min1 or value > max1) and (value < min2 or value > max2):
+            valid = False
+    return valid
+
+with open(fileName) as file:
+    minVal = 1000
+    maxVal = 0
+    for i in range(1000):
+        invalidValues[i] = True
+
+    line = file.readline()
+    while line != "\n":
+        allowed = []
+        name = line[:line.find(":")]
+        ranges = line[line.find(":") + 2:].split("or")
+        for r in ranges:
+            pair = r.split("-")
+            pair[0] = int(pair[0])
+            pair[1] = int(pair[1])
+            allowed.append(pair[0])
+            allowed.append(pair[1])
+            if pair[0] < minVal:
+                minVal = pair[0]
+            if pair[1] > maxVal:
+                maxVal = pair[1]
+            for i in range(pair[0],pair[1] + 1):
+                try:
+                    del invalidValues[i]
+                except:
+                    pass
+        if debug:
+            print(allowed)
+        fields[name] = allowed
+        line = file.readline()
+    if debug:
+        print(invalidValues)
+
+    myTicket = []
+    otherTickets = []
+
+    while line != "your ticket:\n":
+        line = file.readline()
+    line = file.readline()
+    myTicket = line.split(",")
+    for i in range(len(myTicket)):
+        myTicket[i] = int(myTicket[i])
+    
+    while line != "nearby tickets:\n":
+        line = file.readline()
+    line = file.readline()
+    while len(line) > 1:
+        ticket = line.split(",")
+        for i in range(len(ticket)):
+            ticket[i] = int(ticket[i])
+        otherTickets.append(ticket)
+        line = file.readline()
+
+    #validate tickets
+    validTickets = []
+    validTickets.append(myTicket)
+    errorRate = 0
+    for ticket in otherTickets:
+        valid = True
+        for field in ticket:
+            if field in invalidValues:
+                valid = False
+                errorRate += field
+        if valid:
+            validTickets.append(ticket)
+    print(errorRate) #part1
+
+    #get all the values per field
+    fieldUse = []
+    for i in range(len(myTicket)):
+        values = {}
+        for j in range(len(validTickets)):
+            values[validTickets[j][i]] = True
+        fieldUse.append(values)
+
+    fieldNames = defaultdict(list)
+    for i in range(len(fields)):
+        fieldNames[i] = []
+    for field in fields.keys():
+        for i in range(len(fields)):
+            ranges = fields[field]
+            if validateFields(fieldUse[i],ranges[0],ranges[1],ranges[2],ranges[3]):
+                fieldNames[i].append(field)
+    #print(fieldNames)
+
+    possibilities = 0
+    for field in fieldNames:
+        possibilities += len(fieldNames[field])
+
+    while len(fields) < possibilities:
+        if debug:
+            print("-------",len(fields), possibilities)
+        targetDeletion = []
+        for field in fieldNames:
+            if len(fieldNames[field]) == 1:
+                targetDeletion.append(fieldNames[field][0])
+
+        for field in fieldNames:
+            if len(fieldNames[field]) == 1:
+                pass
+            else:
+                newFields = []
+                for name in fieldNames[field]:
+                    if name not in targetDeletion:
+                        newFields.append(name)
+                fieldNames[field] = newFields
+        if debug:
+            print(fieldNames)
+
+        possibilities = 0
+        for field in fieldNames:
+            possibilities += len(fieldNames[field])
+    if debug:
+        print("*****", fieldNames)
+
+    myVal = 1
+    for i in range(len(fieldNames)):
+        if "departure" in fieldNames[i][0]:
+            myVal *= myTicket[i]
+    print(myVal) #part2