hdu3294 manacher算法

#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
const int M=450000;
int len,id,p[M],ans,pos,k;
char T[2],s[M];
int main()
{
    while(~scanf("%s %s",T,s)){
        memset(p,0,sizeof(p));
        len=strlen(s); ans=1; id=0; pos=0; k=T[0]-‘a‘;
        for(int i=len;i>=0;i--) s[i*2+2]=s[i],s[i*2+1]=‘#‘;
        s[0]=‘&‘; len=len*2+1;
        for(int i=2;i<=len;i++){
            if(id+p[id]>i) p[i]=min(p[id*2-i],id+p[id]-i);
            else p[i]=1;
            while(s[i-p[i]]==s[i+p[i]]) p[i]++;
            if(p[i]>ans) ans=p[i],pos=i;
            if(id+p[id]<i+p[i]) id=i;
        }
        int l=(pos-p[pos]+2)/2-1,r=(pos+p[pos]-2)/2-1;
        if((r-l+1)<2){printf("No solution!\n"); continue;}
        printf("%d %d\n",l,r);
        for(int i=pos-p[pos]+2;i<=pos+p[pos]-2;i+=2) printf("%c",(s[i]-‘a‘-k+26)%26+‘a‘); printf("\n");
    }
    return 0;
}