1 files changed, 35 insertions, 0 deletions
diff --git a/content/string/trie.cpp b/content/string/trie.cpp
new file mode 100644
index 0000000..03cf947
--- /dev/null
+++ b/content/string/trie.cpp
@@ -0,0 +1,35 @@
+// Zahlenwerte müssen bei 0 beginnen und zusammenhängend sein.
+constexpr int ALPHABET_SIZE = 2;
+struct node {
+	int words, ends;
+	array<int, ALPHABET_SIZE> nxt;
+	node() : words(0), ends(0) {fill(all(nxt), -1);}
+};
+vector<node> trie = {node()};
+
+int traverse(const vector<int>& word, int x) {
+	int id = 0;
+	for (int c : word) {
+		if (id < 0 || (trie[id].words == 0 && x <= 0)) return -1;
+		trie[id].words += x;
+		if (trie[id].nxt[c] < 0 && x > 0) {
+			trie[id].nxt[c] = sz(trie);
+			trie.emplace_back();
+		}
+		id = trie[id].nxt[c];
+	}
+	trie[id].words += x;
+	trie[id].ends += x;
+	return id;
+}
+
+int insert(const vector<int>& word) {
+	return traverse(word, 1);
+}
+
+bool erase(const vector<int>& word) {
+	int id = traverse(word, 0);
+	if (id < 0 || trie[id].ends <= 0) return false;
+	traverse(word, -1);
+	return true;
+}