Palindrome - POJ 3974 （最长回文子串，Manacher模板）

#include<stdio.h>
#include<string.h>
#include<algorithm>
using namespace std;

const int MAXN = 2e6+7;
const int oo = 1e9+37;

char s[MAXN];
int  p[MAXN];

int Manacher(int len)
{
int id=0, Max=0;

for(int i=2; i<len; i++)
{
p[i] = 1;

if(p[id]+id > i)
p[i] = min(p[id*2-i], p[id]+id-i);
while(s[i+p[i]] == s[i-p[i]])
p[i]++;
if(p[id]+id < p[i]+i)
id = i;

Max = max(Max, p[i]-1);
}

return Max;
}

int main()
{
int t = 1;

while(scanf("%s", s), strcmp(s, "END"))
{
int N = strlen(s);

for(int i=N; i>=0; i--)
{
s[i+i+2] = s[i];
s[i+i+1] = '#';
}
s[0] = '$';

printf("Case %d: %d\n", t++, Manacher(N+N+1));
}

return 0;
}