hash+set Codeforces Round #291 (Div. 2) C. Watto and Mechanism

题目传送门

 /*
     hash+set：首先把各个字符串的哈希值保存在set容器里，然后对于查询的每一个字符串的每一位进行枚举
         用set的find函数查找是否存在替换后的字符串，理解后并不难。另外，我想用64位的自然溢出wa了，不清楚
 */
 /************************************************
 * Author        :Running_Time
 * Created Time  :2015-8-5 13:05:49
 * File Name     :D.cpp
  ************************************************/

 #include <cstdio>
 #include <algorithm>
 #include <iostream>
 #include <sstream>
 #include <cstring>
 #include <cmath>
 #include <string>
 #include <vector>
 #include <queue>
 #include <deque>
 #include <stack>
 #include <list>
 #include <map>
 #include <set>
 #include <bitset>
 #include <cstdlib>
 #include <ctime>
 using namespace std;

 #define lson l, mid, rt << 1
 #define rson mid + 1, r, rt << 1 | 1
 typedef long long ll;
 const int MAXN = 6e5 + ;
 const int INF = 0x3f3f3f3f;
 const int MOD = 1e9 + ;
 const int KEY = ;
 char s[MAXN];
 set<ll> S;
 ll ha[MAXN];
 int n, m;

 void init(void) {
     ha[] = ;
     for (int i=; i<MAXN; ++i)  ha[i] = ha[i-] * KEY % MOD;
 }

 ll get_hash(char *s)    {
     int len = strlen (s);
     ll res = ;
     for (int i=; i<len; ++i)  {
         res = (res * KEY + s[i]) % MOD;
     }
     return res;
 }

 bool judge(char *s) {
     int len = strlen (s);
     ll h = get_hash (s);
     for (int i=; i<len; ++i)   {
         for (ll ch='a'; ch<='c'; ++ch)    {
             if (ch == s[i])   continue;
             if (S.find ((((ch-s[i]) * ha[len-i-] + h) % MOD + MOD) % MOD) != S.end ())    return true;
         }
     }
     return false;
 }

 int main(void)    {     //Codeforces Round #291 (Div. 2) C. Watto and Mechanism
     init ();
     while (scanf ("%d%d", &n, &m) == ) {
         S.clear ();
         for (int i=; i<=n; ++i)    {
             scanf ("%s", s);
             S.insert (get_hash (s));
         }
         for (int i=; i<=m; ++i)    {
             scanf ("%s", s);
             if (judge (s))  puts ("YES");
             else    puts ("NO");
         }
     }

     return ;
 }