day 9 puzzle 1

progress.yaml

@@ -13,4 +13,6 @@
 7:
   stars: 2
 8:
-  stars: 2
+  stars: 2
+9:
+  stars: 1

res/examples/day9_1.txt

@@ -0,0 +1 @@
+12345

res/examples/day9_2.txt

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

src/day9/puzzle1.typ

@@ -0,0 +1,80 @@
+#import "/src/utils.typ": *
+
+#let compute-checksum(blocks) = {
+  let total = 0
+  for (i0, l, id) in blocks {
+    total += id * range(i0, i0 + l).sum()
+  }
+  return total
+}
+
+#let insert(list, elmt) = {
+  for (i, elmt2) in list.enumerate() {
+    if elmt.first() < elmt2.first() {
+      list.insert(i, elmt)
+      return list
+    }
+  }
+  list.push(elmt)
+  return list
+}
+
+#let solve(input) = {
+  let blocks = ()
+  let holes = ()
+
+  let block-i = 0
+  let is-block = true
+  let pos = 0
+  for c in input {
+    let block = (pos, int(c))
+    if is-block {
+      block.push(block-i)
+      block-i += 1
+      blocks.push(block)
+    } else {
+      holes.push(block)
+    }
+    pos += int(c)
+    is-block = not is-block
+  }
+
+  for (hi, hl) in holes {
+    while hl > 0 {
+      if blocks.last().first() < hi + hl {
+        break
+      }
+
+      let (bi, bl, bid) = blocks.pop()
+
+      let len = calc.min(hl, bl)
+
+      blocks.insert(0, (hi, len, bid))
+
+      if len < bl {
+        blocks = insert(blocks, (bi, bl - len, bid))
+      }
+
+      hl -= len
+      hi += len
+    }
+    if hl > 0 {
+      break
+    }
+  }
+  
+  return compute-checksum(blocks)
+}
+
+#show-puzzle(
+  9, 1,
+  solve,
+  example: (
+    "1": 60,
+    "2": 1928
+  ),
+  only-example: true
+)
+
+// Too long to recompile everytime
+#show-result(6390180901651)