From 78f4a7850001903d5315fdc1a68a994fd34b1add Mon Sep 17 00:00:00 2001
From: Matej Focko <me@mfocko.xyz>
Date: Mon, 3 Jun 2024 15:45:14 +0200
Subject: [PATCH] =?UTF-8?q?go:=20add=20=C2=AB208.=20Implement=20Trie=20(Pr?=
 =?UTF-8?q?efix=20Tree)=C2=BB?=
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Signed-off-by: Matej Focko <me@mfocko.xyz>
---
 go/implement-trie-prefix-tree.go | 85 ++++++++++++++++++++++++++++++++
 1 file changed, 85 insertions(+)
 create mode 100644 go/implement-trie-prefix-tree.go

diff --git a/go/implement-trie-prefix-tree.go b/go/implement-trie-prefix-tree.go
new file mode 100644
index 0000000..9e36542
--- /dev/null
+++ b/go/implement-trie-prefix-tree.go
@@ -0,0 +1,85 @@
+package implement_trie_prefix_tree
+
+type TrieNode struct {
+	has        bool
+	successors [26]*TrieNode
+}
+
+type Trie struct {
+	root TrieNode
+}
+
+func Constructor() Trie {
+	return Trie{}
+}
+
+func (this *Trie) Insert(word string) {
+	node := &this.root
+
+	for _, c := range word {
+		idx := int(c) - int('a')
+
+		if node.successors[idx] == nil {
+			node.successors[idx] = new(TrieNode)
+		}
+		node = node.successors[idx]
+	}
+
+	node.has = true
+}
+
+func (this *Trie) findPrefix(prefix string) *TrieNode {
+	node := &this.root
+
+	for _, c := range prefix {
+		idx := int(c) - int('a')
+
+		if node.successors[idx] == nil {
+			return nil
+		}
+		node = node.successors[idx]
+	}
+
+	return node
+}
+
+func (this *Trie) Search(word string) bool {
+	node := this.findPrefix(word)
+	return node != nil && node.has
+}
+
+func (this *Trie) StartsWith(prefix string) bool {
+	var terminates func(*TrieNode) bool
+	terminates = func(node *TrieNode) bool {
+		if node == nil {
+			return false
+		}
+
+		if node.has {
+			return true
+		}
+
+		for _, succ := range node.successors {
+			if terminates(succ) {
+				return true
+			}
+		}
+
+		return false
+	}
+
+	node := this.findPrefix(prefix)
+	if node == nil {
+		return false
+	}
+
+	return terminates(node)
+}
+
+/**
+ * Your Trie object will be instantiated and called as such:
+ * obj := Constructor();
+ * obj.Insert(word);
+ * param_2 := obj.Search(word);
+ * param_3 := obj.StartsWith(prefix);
+ */