Day 8

day08.nim

@@ -0,0 +1,32 @@
+import math, sequtils, strutils
+
+func readNode(input: seq[string], start: int): tuple[value: int, metasum: int, offset: int] =
+    let
+        child_count = input[start + 0].parseInt
+        meta_count = input[start + 1].parseInt
+    var
+        value = 0
+        metasum = 0
+        offset = start + 2
+        child_values: seq[int]
+    
+    for i in 0 .. child_count - 1:
+        var res = readNode(input, offset)
+        child_values.add(res.value)
+        offset = res.offset
+        metasum += res.metasum
+
+    for m in input[offset .. offset + meta_count - 1]:
+        var v = m.parseInt
+        if v > 0 and v - 1 < child_count:
+            value += child_values[v - 1]
+        metasum += v
+    offset += meta_count
+    
+    if child_count == 0:
+        value = metasum
+    (value, metasum, offset)
+
+let root = readNode(readFile("data/08.txt").strip.split(" "), 0)
+echo root.metasum
+echo root.value