1355: [Baltic2009]Radio Transmission

 1 #include<iostream>
 2 #include<cstdio>
 3 #include<cstring>
 4 #include<cmath>
 5 #include<cstring>
 6 #include<algorithm>
 7 using namespace std;
 8 const int MAXN=1000010;
 9 void read(int &n)
10 {
11     char c=‘+‘;int x=0;bool flag=0;
12     while(c<‘0‘||c>‘9‘){c=getchar();if(c==‘-‘)flag=1;}
13     while(c>=‘0‘&&c<=‘9‘)x=x*10+c-48,c=getchar();
14     n=flag==1?-x:x;
15 }
16 char a[MAXN];
17 int p[MAXN];
18 int l=0;
19 void getp()
20 {
21     int j=0;
22     for(int i=1;i<l;i++)
23     {
24         while(a[i]!=a[j]&&j>0)    j=p[j-1];
25         if(a[i]==a[j])j++;
26         p[i]=j;
27     }
28     printf("%d",l-p[l-1]);
29 }
30 int main()
31 {
32     int meiyong;read(meiyong);
33     scanf("%s",a);
34     l=strlen(a);
35     getp();
36     return 0;
37 }