d09

res/09/example

@@ -0,0 +1 @@
+2333133121414131402

src/days/d09.rs

@@ -6,11 +6,115 @@ pub fn solve() {
     #[allow(unused)]
     let contents = fs::read_to_string(path).expect("Something went wrong reading the file");
 
-    let result: usize = 0;
+    let orig_filesystem: Vec<isize> = contents
+        .chars()
+        .filter(|c| c.is_digit(10))
+        .enumerate()
+        .map(|(i, c)| {
+            if i % 2 == 0 {
+                vec![(i / 2) as isize; c.to_string().parse::<usize>().unwrap()]
+            } else {
+                vec![-1; c.to_string().parse::<usize>().unwrap()]
+            }
+        })
+        .flatten()
+        .collect();
+
+    let mut filesystem = orig_filesystem.clone();
+
+    let mut start = 0;
+    let mut end = filesystem.len() - 1;
+
+    loop {
+        while filesystem[start] != -1 {
+            start += 1;
+        }
+
+        while filesystem[end] == -1 {
+            end -= 1;
+        }
+
+        if start >= end {
+            break;
+        }
+
+        filesystem.swap(start, end);
+    }
+
+    let result: usize = filesystem
+        .iter()
+        .enumerate()
+        .map(|(i, n)| if *n == -1 { 0 } else { i * *n as usize })
+        .sum();
 
     println!("Result 1: {}", result);
 
-    let result: usize = 0;
+    let mut filesystem = orig_filesystem.clone();
+
+    let mut free_space: Vec<(usize, usize)> = Vec::new();
+    let mut iter = 0;
+    while iter < filesystem.len() {
+        if filesystem[iter] == -1 {
+            let mut count = 0;
+            while filesystem[iter] == -1 {
+                count += 1;
+                iter += 1;
+            }
+            free_space.push((iter - count, count));
+        } else {
+            iter += 1;
+        }
+    }
+
+    let mut iter = filesystem.len() - 1;
+    while iter > 0 {
+        while filesystem[iter] == -1 {
+            if iter == 0 {
+                break;
+            }
+            iter -= 1;
+        }
+        let typ = filesystem[iter];
+        let end = iter;
+        let mut start = iter;
+        while filesystem[start] == typ {
+            if start == 0 {
+                break;
+            }
+            start -= 1;
+        }
+        start += 1;
+        let len = end - start + 1;
+
+        if len == 0 {
+            continue;
+        }
+
+        let res = filesystem
+            .windows(len)
+            .enumerate()
+            .find(|(_, win)| win.iter().all(|c| *c == -1));
+        if res.is_none() {
+            iter = start - 1;
+            continue;
+        }
+        let (start_i, _) = res.unwrap();
+
+        if start_i >= start {
+            iter = start - 1;
+            continue;
+        }
+
+        for i in 0..len {
+            filesystem.swap(start_i + i, start + i);
+        }
+    }
+
+    let result: usize = filesystem
+        .iter()
+        .enumerate()
+        .map(|(i, n)| if *n == -1 { 0 } else { i * *n as usize })
+        .sum();
 
     println!("Result 2: {}", result);
 }