Added Day 5 Part 1

small.input

@@ -1,13 +1,4 @@
-ecl:gry pid:860033327 eyr:2020 hcl:#fffffd
-byr:1937 iyr:2017 cid:147 hgt:183cm
-
-iyr:2013 ecl:amb cid:350 eyr:2023 pid:028048884
-hcl:#cfa07d byr:1929
-
-hcl:#ae17e1 iyr:2013
-eyr:2024
-ecl:brn pid:760753108 byr:1931
-hgt:179cm
-
-hcl:#cfa07d eyr:2025 pid:166559648
-iyr:2011 ecl:brn hgt:59in
+FBFBBFFRLR
+BFFFBBFRRR
+FFFBBBFRRR
+BBFFBBFRLL

src/main.rs

@@ -1,88 +1,58 @@
-use std::collections::HashMap;
 use std::io::{stdin, Read};
 
 fn main() {
     let mut input = String::new();
     stdin().read_to_string(&mut input).unwrap();
 
-    let passports: usize = input
-        .split("\n\n")
+    let max_seat_id: usize = input
+        .split('\n')
         .filter(|x| !x.is_empty())
         .into_iter()
-        .map(|x| x.replace('\n', " "))
-        .map(|x| {
-            let mut map = HashMap::new();
+        .map(|seat| {
+            let seat = seat.as_bytes();
+            let (region, columns) = seat.split_at(7);
 
-            x.split(' ').filter(|x| !x.is_empty()).for_each(|y| {
-                let mut y = y.split(':');
-                let key = y.next().unwrap();
-                let value = y.next().unwrap();
+            let mut lower = 0;
+            let mut upper = 127;
 
-                map.insert(key.to_owned(), value.to_owned());
-            });
-
-            map
-        })
-        .filter(|map| {
-            validate(&map, "byr")
-                && validate(&map, "iyr")
-                && validate(&map, "eyr")
-                && validate(&map, "hgt")
-                && validate(&map, "hcl")
-                && validate(&map, "ecl")
-                && validate(&map, "pid")
-        })
-        .count();
-
-    println!("{:?}", passports);
-}
-
-fn validate(map: &HashMap<String, String>, key: &str) -> bool {
-    match (key, map.get(key)) {
-        ("byr", Some(v)) => {
-            let byr = v.parse::<i32>().unwrap();
-            byr >= 1920 && byr <= 2002
-        }
-        ("iyr", Some(v)) => {
-            let iyr = v.parse::<i32>().unwrap();
-            iyr >= 2010 && iyr <= 2020
-        }
-        ("eyr", Some(v)) => {
-            let eyr = v.parse::<i32>().unwrap();
-            eyr >= 2020 && eyr <= 2030
-        }
-        ("hgt", Some(v)) => {
-            if v.contains("cm") {
-                let v = v.trim_end_matches(char::is_alphabetic);
-                let v = v.parse::<i32>().unwrap();
-                v >= 150 && v <= 193
-            } else if v.contains("in") {
-                let v = v.trim_end_matches(char::is_alphabetic);
-                let v = v.parse::<i32>().unwrap();
-                v >= 59 && v <= 76
-            } else {
-                false
+            for r in region {
+                match r {
+                    b'F' => {
+                        let mid = (lower + upper) / 2;
+                        upper = mid;
+                    }
+                    b'B' => {
+                        let mid = (lower + upper + 1) / 2;
+                        lower = mid;
+                    }
+                    _ => unreachable!(),
+                }
             }
-        }
-        ("hcl", Some(v)) => {
-            v.starts_with('#')
-                && v.chars()
-                    .skip(1)
-                    .filter(|x| match x {
-                        '0'..='9' => true,
-                        'a'..='f' => true,
-                        _ => false,
-                    })
-                    .count()
-                    == 6
-        }
-        ("ecl", Some(v)) => match v.as_ref() {
-            "amb" | "blu" | "brn" | "gry" | "grn" | "hzl" | "oth" => true,
-            _ => false,
-        },
-        ("pid", Some(v)) => v.len() == 9 && v.chars().filter(|&x| char::is_numeric(x)).count() == 9,
-        ("cid", _) => true,
-        (_, None) => false,
-        (_, _) => unreachable!(),
-    }
+
+            let region = lower;
+            lower = 0;
+            upper = 7;
+
+            for col in columns {
+                match col {
+                    b'L' => {
+                        let mid = (lower + upper) / 2;
+                        upper = mid;
+                    }
+                    b'R' => {
+                        let mid = (lower + upper + 1) / 2;
+                        lower = mid;
+                    }
+                    _ => unreachable!(),
+                }
+            }
+
+            let col = lower;
+
+            region * 8 + col
+        })
+        .max()
+        .unwrap();
+
+    println!("{:?}", max_seat_id);
 }