day 04

examples/day03_1_rewrite.rs

@@ -0,0 +1,14 @@
+fn main() {
+    println!("{}", std::io::stdin().lines()
+        .map(|x| x.unwrap())
+        .map(|line| (
+            line.chars().take(line.len() / 2).collect::<Vec<char>>(), 
+            line.chars().skip(line.len() / 2).collect::<Vec<char>>()
+        )).map(|(a, b)| *a.iter().filter(|c| b.contains(c)).next().unwrap())
+        .map(|c| match c {
+            'a'..='z' => (c as u32) - ('a' as u32) + 1,
+            'A'..='Z' => (c as u32) - ('A' as u32) + 27,
+            _ => unreachable!()
+        }).reduce(|a, b| a + b)
+        .unwrap());
+}

examples/day03_2_rewrite.rs

@@ -0,0 +1,17 @@
+fn main() {
+    let lines = std::io::stdin().lines()
+        .map(|x| x.unwrap())
+        .collect::<Vec<String>>();
+    let result = lines.chunks(3)
+        .map(|chunk| 
+            chunk[0].chars()
+                .filter(|c| chunk[1].contains(*c) && chunk[2].contains(*c))
+                .next().unwrap()
+        ).map(|c| match c {
+            'a'..='z' => (c as u32) - ('a' as u32) + 1,
+            'A'..='Z' => (c as u32) - ('A' as u32) + 27,
+            _ => unreachable!()
+        }).reduce(|a, b| a + b)
+        .unwrap();
+    println!("{}", result);
+}

examples/day04_1.rs

@@ -0,0 +1,14 @@
+use std::collections::*;
+
+fn main() {
+    let lines: Vec<String> = std::io::stdin().lines().map(|x| x.unwrap()).collect();
+    let mut result = 0;
+    for line in lines {
+        let elves = line.split(",").map(|x| x.split("-").map(|s| s.parse().unwrap()).collect()).collect::<Vec<Vec<i32>>>();
+        if elves[0][0] <= elves[1][0] && elves[0][1] >= elves[1][1]
+        || elves[0][0] >= elves[1][0] && elves[0][1] <= elves[1][1] {
+            result += 1;
+        }
+    }
+    println!("{}", result);
+}

examples/day04_2.rs

@@ -0,0 +1,14 @@
+use std::collections::*;
+
+fn main() {
+    let lines: Vec<String> = std::io::stdin().lines().map(|x| x.unwrap()).collect();
+    let mut result = 0;
+    for line in lines {
+        let elves = line.split(",").map(|x| x.split("-").map(|s| s.parse().unwrap()).collect()).collect::<Vec<Vec<i32>>>();
+        if elves[0][1] >= elves[1][0] && elves[1][1] >= elves[0][0]
+        || elves[0][1] <= elves[1][0] && elves[1][1] <= elves[0][0] {
+            result += 1;
+        }
+    }
+    println!("{}", result);
+}