Trie data structure using pointers

trie.cpp

#include <bits/stdc++.h>

using namespace std;

int n, m;
string s;

struct trie {
	trie *next[26];
	int count;
	bool end;

	trie() {
		memset(next, 0, sizeof next);
		count = 0;
		end = false;
	}
};

trie *root;

void insert(string s) {
	trie *current = root;

	for(int i = 0; i < s.length(); ++i) {
		int idx = s[i] - 'a';

		if(current->next[idx] == NULL) {
			current->next[idx] = new trie();
		}

		current = current->next[idx];

		++current->count;
	}

	current->end = true;
}

bool find(string s) {
	trie *current = root;

	for(int i = 0; i < s.length(); ++i) {
		int idx = s[i] - 'a';

		if(current->next[idx] == NULL) {
			return false;
		}

		current = current->next[idx];
	}

	return current->end;
}

void freeTrie(trie *current) {
	if(current == NULL) {
		return;
	}

	for(int i = 0; i < 26; ++i) {
		freeTrie(current->next[i]);
	}

	delete [] current;
}

int main() {
#ifndef ONLINE_JUDGE
	freopen("input.in", "r", stdin);
#endif

	root = new trie();

	scanf("%d %d", &n, &m);

	for(int i = 0; i < n; i++) {
		cin >> s;
		insert(s);
	}

	for(int i = 0; i < m; ++i) {
		cin >> s;
		if(find(s)) {
			puts("YES");
		} else {
			puts("NO");
		}
	}

	freeTrie(root);

	return 0;
}