adding string chapter

1 files changed, 25 insertions, 0 deletions

diff --git a/string/trie.cpp b/string/trie.cpp
new file mode 100644
index 0000000..f4b979c
--- /dev/null
+++ b/string/trie.cpp
@@ -0,0 +1,25 @@
+//nur fuer kleinbuchstaben!
+struct node {
+	node *(e)[26];
+	int c = 0;//anzahl der woerter die an dem node enden.
+	node() { for(int i = 0; i < 26; i++) e[i] = NULL; }	
+};
+
+void insert(node *root, string *txt, int s) {
+	if(s >= txt->length()) root->c++;
+	else {
+		int idx = (int)((*txt).at(s) - 'a');
+		if(root->e[idx] == NULL) {
+			root->e[idx] = new node();
+		}
+		insert(root->e[idx], txt, s+1);
+	}
+}
+
+int contains(node *root, string *txt, int s) {
+	if(s >= txt->length()) return root->c;
+	int idx = (int)((*txt).at(s) - 'a');
+	if(root->e[idx] != NULL) {
+			return contains(root->e[idx], txt, s+1);
+	} else return 0;
+}