1 files changed, 106 insertions, 0 deletions
diff --git a/2024/day05.rs b/2024/day05.rs
new file mode 100644
index 0000000..bf4303a
--- /dev/null
+++ b/2024/day05.rs
@@ -0,0 +1,106 @@
+#![allow(dead_code)]
+#![allow(unused_variables)]
+#![allow(unused_mut)]
+use std::env;
+use std::fs::File;
+use std::io::Read;
+
+fn is_valid(update: &Vec<usize>, rules: &Vec<(usize, usize)>) -> bool {
+    for (i, n) in update.iter().enumerate() {
+        for (l, r) in rules {
+            if n == l {
+                if let Some(pr) = update.iter().position(|a| a == r) {
+                    if pr < i {
+                        return false;
+                    }
+                }
+            }
+            if n == r {
+                if let Some(pl) = update.iter().position(|a| a == l) {
+                    if pl > i {
+                        return false;
+                    }
+                }
+            }
+        }
+    }
+
+    true
+}
+
+fn make_valid(update: &Vec<usize>, rules: &Vec<(usize, usize)>) -> Vec<usize> {
+    let mut uv = update.clone();
+    for i in 0..uv.len() {
+        let n = uv[i];
+        for (l, r) in rules {
+            if n == *l {
+                if let Some(pr) = uv.iter().position(|a| a == r) {
+                    if pr < i {
+                        uv[pr] = n;
+                        uv[i] = *r;
+                        break;
+                    }
+                }
+            }
+            if n == *r {
+                if let Some(pl) = uv.iter().position(|a| a == l) {
+                    if i < pl {
+                        uv[pl] = n;
+                        uv[i] = *l;
+                        break;
+                    }
+                }
+            }
+        }
+    }
+
+    uv
+}
+
+fn main() {
+    let args: Vec<String> = env::args().collect();
+    let filename = if args.len() == 1 {
+        "in/".to_owned() + args[0].split('/').last().unwrap() + ".pzl"
+    } else {
+        args[1].clone()
+    };
+    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 (paragraph1, paragraph2) = content.trim_end().split_once("\n\n").unwrap();
+    let paragraph1 = paragraph1.trim_end().split("\n");
+    let paragraph2 = paragraph2.trim_end().split("\n");
+
+    let mut rules: Vec<(usize, usize)> = Vec::new();
+    for line in paragraph1 {
+        let (a, b) = line.split_once("|").unwrap();
+        rules.push((a.parse().unwrap(), b.parse().unwrap()));
+    }
+    //println!("{:?}", rules);
+
+    let mut updates: Vec<Vec<usize>> = Vec::new();
+    for line in paragraph2 {
+        updates.push(line.split(",").map(|a| a.parse().unwrap()).collect());
+    }
+    //println!("{:?}", updates);
+
+    let mut res1 = 0;
+    let mut res2 = 0;
+    for u in updates {
+        let ret = is_valid(&u, &rules);
+        if ret {
+            res1 += u[u.len() / 2];
+        } else {
+            let mut uv = make_valid(&u, &rules);
+            while !is_valid(&uv, &rules) {
+                uv = make_valid(&uv, &rules);
+            }
+            res2 += uv[uv.len() / 2];
+        }
+    }
+
+    println!("res1: {}", res1);
+    println!("res2: {}", res2);
+    assert_eq!(res1, 4766);
+    assert_eq!(res2, 6257);
+}