SCU-4438 Censor（字符串HASH）

哈希模板：挑战程序设计P374

Censor

frog is now a editor to censor so-called sensitive words (敏感词).

She has a long text pp. Her job is relatively simple -- just to find the first occurence of sensitive word ww and remove it.

frog repeats over and over again. Help her do the tedious work.

Input

The input consists of multiple tests. For each test:

The first line contains 11 string ww. The second line contains 11 string pp.

(1≤length of w,p≤5⋅1061≤length of w,p≤5⋅106, w,pw,p consists of only lowercase letter)

Output

For each test, write 11 string which denotes the censored text.

Sample Input

    abc
    aaabcbc
    b
    bbb
    abc
    ab

Sample Output

    a
    
    ab

题意：每次删去字符串b中的a串，输出最终剩余的字符

思路： 将a串哈希为一个整数，将b字符依次放入栈中，当长度大于等于a串的长度时，比较哈希值，相同则删除，继续操作

CODE：

#include
#include
#include
#include
#include
#include
using namespace std;
typedef unsigned long long ull;
const ull B =1e8+7;//哈希的基数  
const int N=5*1e6+10;
ull bh[N];
char a[N],b[N],str[N];
int main()
{
    while(~scanf("%s%s",a,b))
    {
        int a1=strlen(a),b1=strlen(b);
        if(a1>b1)
        {
            printf("%s\n",b);
            continue;
        }
        ull t=1;
       for(int i=0; i=a1&&bh[top]-bh[top-a1]*t==ah)
            {
                //printf("%d\n",top);
                top-=a1;
            }

        }
       for(int i=0;i