Codeforces Round #291 (Div. 2) C - Watto and Mechanism

#include <iostream>
#include <queue>
#include <stack>
#include <map>
#include <set>
#include <bitset>
#include <cstdio>
#include <algorithm>
#include <cstring>
#include <climits>
#include <cstdlib>
#include <cmath>
#include <time.h>
#define maxn 600005
#define maxm 200005
#define eps 1e-7
#define mod 1000000007
#define INF 0x3f3f3f3f
#define PI (acos(-1.0))
#define lowbit(x) (x&(-x))
#define mp make_pair
#define ls o<<1
#define rs o<<1 | 1
#define lson o<<1, L, mid 
#define rson o<<1 | 1, mid+1, R
#define pii pair<int, int>
#pragma comment(linker, "/STACK:16777216")
typedef long long LL;
typedef unsigned long long ULL;
using namespace std;
LL qpow(LL a, LL b){LL res=1,base=a;while(b){if(b%2)res=res*base;base=base*base;b/=2;}return res;}
LL powmod(LL a, LL b){LL res=1,base=a;while(b){if(b%2)res=res*base%mod;base=base*base%mod;b/=2;}return res;}
//head

int next[maxn][3];
int end[maxn];
char s[maxn];
int root = 1, tail, n, m, ok;

void read()
{
	int u;
	tail = 2;
	scanf("%d%d", &n, &m);
	for(int i = 1; i <= n; i++) {
		scanf("%s", s);
		u = root;
		for(int j = 0; s[j]; j++) {
			int c = s[j] - 'a';
			if(!next[u][c]) next[u][c] = tail++;
			u = next[u][c];
		}
		end[u] = true;
	}
}

void dfs(int u, int dep, int k)
{
	if(dep == n && k && end[u]) ok = true;
	if(ok) return;
	if(dep > n) return;
	int c = s[dep] - 'a';
	if(next[u][c]) dfs(next[u][c], dep + 1, k);
	if(!k) for(int i = 0; i < 3; i++) if(i != c && next[u][i]) dfs(next[u][i], dep + 1, 1);
}

void work()
{
	while(m--) {
		scanf("%s", s);
		n = strlen(s);
		ok = 0;
		dfs(root, 0, 0);
		if(ok) printf("YES
");
		else printf("NO
");
	}
}

int main()
{
	read();
	work();
	
	
	return 0;
}