Bzoj 3942——Censoring（KMP）

 1 #include<cstdio>
 2 #include<iostream>
 3 #include<cmath>
 4 #include<cstring>
 5 #include<algorithm>
 6 #include<cstdlib>
 7 using namespace std;
 8 char s1[1000005],s2[1000005],s[1000005];
 9 int n,m,p[1000005],next[1000005],top;
10 int main()
11 {
12     gets(s1+1); gets(s2+1);
13     n=strlen(s1+1); m=strlen(s2+1);
14     p[1]=0; int j=0;
15     for (int i=1; i<=n; i++){
16         while (j>0 && s2[j+1]!=s2[i+1]) j=p[j];
17         if (s2[j+1]==s2[i+1]) j++;
18         p[i+1]=j;
19     }
20     next[0]=0;
21     for (int i=1; i<=n; i++){
22         s[++top]=s1[i];
23         int j=next[top-1];
24         while (j>0 && s2[j+1]!=s[top]) j=p[j];
25         if (s2[j+1]==s[top]) j++;
26         next[top]=j;
27         if (next[top]==m) top-=m;
28     }
29     for (int i=1; i<=top; i++) putchar(s[i]); putchar(‘\n‘);
30     return 0;
31 }