给一个字符串,求最长回文字串有多长

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#include
     
      #include
      
       #include
       
        #define N 1000005using namespace std;int n,m,T,p[N*2],ans;char s[2*N],t[N];void manacher(){    int id=0,pos=0,x=0;    for (int i=1;i<+n;i++)    {	if (pos>i) x=min(p[id*2-i],pos-i);	else x=1;	while (s[i-x]==s[i+x]) x++;	if (i+x>pos) pos=i+x,id=i;	p[i]=x;    }}int main(){    while (scanf("%s",t+1) && t[1]!='E')    {	ans=0;	m=strlen(t+1);	s[n=0]='!';	for (int i=1;i<=m;i++)	{	    s[++n]='#';	    s[++n]=t[i];	}	s[++n]='#';	s[n+1]='?';	manacher();	for (int i=1;i<=n;i++)	    ans=max(ans,p[i]);	printf("Case %d: %d\n",++T,ans-1);    }    return 0;}