1 files changed, 65 insertions, 0 deletions
diff --git a/2023/day04.rs b/2023/day04.rs
new file mode 100644
index 0000000..0bed2c7
--- /dev/null
+++ b/2023/day04.rs
@@ -0,0 +1,65 @@
+#![allow(dead_code)]
+#![allow(unused_variables)]
+#![allow(unused_mut)]
+use std::fs::File;
+use std::io::Read;
+
+fn main() {
+    // let filename = "in/day04.ref";
+    let filename = "in/day04.pzl";
+
+    let mut f = File::open(filename).expect("cannot open file");
+    let mut content = String::new();
+    f.read_to_string(&mut content).expect("cannot read file");
+    let lines: Vec<_> = content.trim_end().split('\n').collect();
+    // println!("{:?}", lines);
+
+    let mut res1 = 0;
+
+    let mut counts: Vec<i32> = Vec::new();
+
+    for line in &lines {
+        let s1: Vec<&str> = line.split(":").collect();
+        let game_num: u32 = s1[0]
+            .replace("  ", " ")
+            .replace("  ", " ")
+            .split(" ")
+            .collect::<Vec<&str>>()[1]
+            .parse()
+            .unwrap();
+        let s2: Vec<&str> = s1[1].trim().split("|").collect::<Vec<&str>>();
+
+        let winning: Vec<u32> = s2[0]
+            .trim()
+            .replace("  ", " ")
+            .split(" ")
+            .map(|x| x.parse::<u32>().unwrap())
+            .collect();
+        let actual: Vec<u32> = s2[1]
+            .trim()
+            .replace("  ", " ")
+            .replace("  ", " ")
+            .split(" ")
+            .map(|x| x.parse::<u32>().unwrap())
+            .collect();
+
+        let count: i32 = actual.iter().filter(|x| winning.contains(x)).count() as i32;
+        counts.push(count);
+        // println!("{}", count);
+        res1 += 1_i32.checked_shl((count - 1) as u32).unwrap_or(0);
+    }
+    let mut copies: Vec<i32> = vec![0; counts.len()];
+
+    for i in 0..counts.len() {
+        for j in i..i + counts[i] as usize {
+            copies[j + 1] += 1 + copies[i];
+        }
+    }
+
+    let res2 = copies.iter().sum::<i32>() + copies.len() as i32;
+
+    println!("res1: {}", res1);
+    println!("res2: {}", res2);
+    assert_eq!(res1, 21919);
+    assert_eq!(res2, 9881048);
+}