C - Censor SCU - 4438

Censor

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

She has a long text  

. Her job is relatively simple -- just to find the first occurence of sensitive word  

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  

string   . The second line contains   string  

.

(   

,  

consists of only lowercase letter)

Output

For each test, write  

string which denotes the censored text.

Sample Input

    abc
    aaabcbc
    b
    bbb
    abc
    ab

Sample Output

    a
    
    ab

#include<bits/stdc++.h>

using namespace std;
const int maxn=5e6+10;

char str[maxn],s[maxn];

struct node{
    char ch;
    int val;
    node(){}
    node(char _ch,int _val):ch(_ch),val(_val){}
};

node stk[maxn];
int top;
int f[maxn];
/*
模式串和文本串的比较
abc
aaabcbabccc
还是比较难受的，当时只是想到了栈这个数据结构，但是没有想到kmp,来匹配
导致匹配一直出现问题，还是做的少啊
*/
void solve(int l1,int l2){
    top=-1;
    int j=0;
    for(int i=0;i<l2;i++){
        if(top==-1)j=0;
        else j=stk[top].val;

        while(j&&str[i]!=s[j])j=f[j];
        if(str[i]==s[j])j++;
        stk[++top]=node(str[i],j);
        if(j==l1){
            top-=l1;
        }
    }
}

void get_f(int l){
    f[0]=f[1]=0;
    for(int i=1;i<l;i++){
        int j=f[i];
        while(j&&s[i]!=s[j])j=f[j];
        f[i+1]=s[i]==s[j]?j+1:0;
    }
}

int main()
{
    while(scanf("%s %s",s,str)==2){
        int len1=strlen(s),len2=strlen(str);
        if(len1>len2){
            printf("%s\n",str);
            continue;
        }
        get_f(len1);
        solve(len1,len2);
        for(int i=0;i<=top;i++)printf("%c",stk[i].ch);
        printf("\n");
    }
    return 0;
}