BZOJ 1355[Baltic2009]Radio Transmission

 1 #include<set>
 2 #include<queue>
 3 #include<cstdio>
 4 #include<cstdlib>
 5 #include<cstring>
 6 #include<iostream>
 7 #include<algorithm>
 8 using namespace std;
 9 const int N = 1000010;
10 #define For(i,n) for(int i=1;i<=n;i++)
11 #define Rep(i,l,r) for(int i=l;i<=r;i++)
12 char st[N];
13 int n,next[N];
14 
15 void BuildNext(){
16     next[0]=next[1]=0;
17     For(i,n){
18         int j=next[i];
19         while(j&&st[i]!=st[j]) j=next[j];
20         if(st[i]==st[j]) next[i+1]=j+1;
21         else             next[i+1]=0;
22     }
23 }
24 
25 int main(){
26     scanf("%d",&n);
27     scanf("%s",&st);
28     BuildNext();
29     printf("%d\n",n-next[n]);
30     return 0;
31 }