Add Trie

Author: EloToJaa

Trie.cpp

@@ -0,0 +1,51 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+class TrieNode {
+public:
+  int nextNode[26];
+  bool isEnd;
+  TrieNode() : isEnd(false) { memset(nextNode, -1, sizeof(nextNode)); }
+};
+
+class Trie {
+public:
+  vector<TrieNode> trie;
+
+  Trie() { trie.push_back(TrieNode()); }
+
+  void insert(string word) {
+    int node = 0;
+    for (const char &c : word) {
+      if (trie[node].nextNode[c - 'a'] == -1) {
+        trie[node].nextNode[c - 'a'] = trie.size();
+        trie.push_back(TrieNode());
+      }
+      node = trie[node].nextNode[c - 'a'];
+    }
+    trie[node].isEnd = true;
+  }
+
+  bool search(string word) {
+    int node = 0;
+    for (const char &c : word) {
+      if (trie[node].nextNode[c - 'a'] == -1) {
+        return false;
+      }
+      node = trie[node].nextNode[c - 'a'];
+    }
+    return trie[node].isEnd;
+  }
+
+  bool startsWith(string prefix) {
+    int node = 0;
+    for (const char &c : prefix) {
+      if (trie[node].nextNode[c - 'a'] == -1) {
+        return false;
+      }
+      node = trie[node].nextNode[c - 'a'];
+    }
+    return true;
+  }
+};