37 lines
774 B
Go
37 lines
774 B
Go
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package main
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import (
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"fmt"
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"internal/day08"
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"internal/util"
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)
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func main() {
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data := util.ReadInputInts()
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root := day08.BuildTree(data)
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fmt.Println(generateChecksum(root))
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}
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func generateChecksum(node *day08.Node) int {
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// If a node has no child nodes, its value is the sum of its metadata entries.
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if len(node.Children) == 0 {
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return node.SumMetadata()
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}
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// if a node does have child nodes, the metadata entries become (1-indexed) indexes
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// which refer to those child nodes.
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// The value of the node is the sum of the values of its children.
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value := 0
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for _, md := range node.Metadata {
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// Skip invalid metadata entries
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if md == 0 || md > len(node.Children) {
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continue
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}
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value += generateChecksum(node.Children[md-1])
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}
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return value
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}
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