added visualization for day 9 puzzle 1

src/day9/puzzle1.typ

@@ -1,5 +1,28 @@
 #import "/src/utils.typ": *
 
+#let parse-input(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
+  }
+  
+  return (blocks, holes)
+}
+
 #let compute-checksum(blocks) = {
   let total = 0
   for (i0, l, id) in blocks {
@@ -20,24 +43,7 @@
 }
 
 #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
-  }
+  let (blocks, holes) = parse-input(input)
 
   for (hi, hl) in holes {
     while hl > 0 {
@@ -66,6 +72,70 @@
   return compute-checksum(blocks)
 }
 
+#let visualize(input) = {
+  let (blocks, holes) = parse-input(input)
+  let max-id = blocks.last().last()
+
+  let col-gradient = gradient.linear(red, orange, yellow, green, aqua, blue, purple)
+
+  let show-fs(size, blocks) = {
+    let cells = ()
+    for (bi, bl, bid) in blocks {
+      cells.push(
+        grid.cell(
+          x: bi,
+          colspan: bl,
+          fill: col-gradient.sample(bid * 100% / max-id),
+          str(bid)
+        )
+      )
+    }
+    grid(
+      columns: (1fr,) * size,
+      align: center + horizon,
+      stroke: black,
+      inset: 0.3em,
+      ..cells
+    )
+  }
+
+  let last-block = blocks.last()
+  let last-holes = holes.last()
+  let show-fs = show-fs.with(
+    calc.max(
+      last-block.first() + last-block.at(1),
+      last-holes.first() + last-holes.last()
+    )
+  )
+  let steps = ()
+  steps.push(show-fs(blocks))
+
+  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
+    }
+    steps.push(show-fs(blocks))
+  }
+
+  stack(
+    spacing: 0.5em,
+    ..steps
+  )
+}
+
 #show-puzzle(
   9, 1,
   solve,
@@ -73,7 +143,8 @@
     "1": 60,
     "2": 1928
   ),
-  only-example: true
+  only-example: true,
+  visualize: visualize
 )
 
 // Too long to recompile everytime

src/day9/puzzle2.typ

@@ -27,13 +27,12 @@
   let is-block = true
   let pos = 0
   for c in input {
-    let block = (pos, int(c))
+    let size = int(c)
     if is-block {
-      block.push(block-i)
+      blocks.push((pos, size, block-i))
       block-i += 1
-      blocks.push(block)
     } else {
-      holes.push(block)
+      holes.push((pos, size))
     }
     pos += int(c)
     is-block = not is-block
@@ -46,6 +45,9 @@
         bi = hi
         holes.at(i).first() += bl
         holes.at(i).last() -= bl
+        if bl == hl {
+          holes.remove(i)
+        }
         break
       }
     }