part1 (2373B)
1--- Day 4: Passport Processing --- 2 3You arrive at the airport only to realize that you grabbed your North Pole Credentials instead of 4your passport. While these documents are extremely similar, North Pole Credentials aren't issued by 5a country and therefore aren't actually valid documentation for travel in most of the world. 6 7It seems like you're not the only one having problems, though; a very long line has formed for the 8automatic passport scanners, and the delay could upset your travel itinerary. 9 10Due to some questionable network security, you realize you might be able to solve both of these 11problems at the same time. 12 13The automatic passport scanners are slow because they're having trouble [1m[37mdetecting which 14passports have all required fields[0m. The expected fields are as follows: 15 16- byr (Birth Year) - iyr (Issue Year) - eyr (Expiration Year) - hgt (Height) - hcl (Hair Color) - 17ecl (Eye Color) - pid (Passport ID) - cid (Country ID) 18 19Passport data is validated in batch files (your puzzle input). Each passport is represented as a 20sequence of key:value pairs separated by spaces or newlines. Passports are separated by blank lines. 21 22Here is an example batch file containing four passports: 23 24ecl:gry pid:860033327 eyr:2020 hcl:#fffffd byr:1937 iyr:2017 cid:147 hgt:183cm 25 26iyr:2013 ecl:amb cid:350 eyr:2023 pid:028048884 hcl:#cfa07d byr:1929 27 28hcl:#ae17e1 iyr:2013 eyr:2024 ecl:brn pid:760753108 byr:1931 hgt:179cm 29 30hcl:#cfa07d eyr:2025 pid:166559648 iyr:2011 ecl:brn hgt:59in 31 32The first passport is [1m[37mvalid[0m - all eight fields are present. The second passport is 33[1m[37minvalid[0m - it is missing hgt (the Height field). 34 35The third passport is interesting; the [1m[37monly missing field[0m is cid, so it looks like data 36from North Pole Credentials, not a passport at all! Surely, nobody would mind if you made the system 37temporarily ignore missing cid fields. Treat this "passport" as [1m[37mvalid[0m. 38 39The fourth passport is missing two fields, cid and byr. Missing cid is fine, but missing any other 40field is not, so this passport is [1m[37minvalid[0m. 41 42According to the above rules, your improved system would report [1m[37m2[0m valid passports. 43 44Count the number of [1m[37mvalid[0m passports - those that have all required fields. Treat cid as 45optional. [1m[37mIn your batch file, how many passports are valid?[0m 46 47