HDOJ 3068 最大回文数

#include<iostream>
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<string>
#include<queue>
#include<algorithm>
#include<map>
#include<iomanip>
#define INF 99999999
using namespace std;

const int MAX=110000+10;
char s[MAX*2];
int p[MAX*2];

int main(){
    while(scanf("%s",s)!=EOF){
        int len=strlen(s),id=0,maxlen=0;
        for(int i=len;i>=0;--i){//插入'#'
            s[i+i+2]=s[i];
            s[i+i+1]='#';
        }//插入了len+1个'#',最终的s长度是1~len+len+1即2*len+1,首尾s[0]和s[2*len+2]要插入不同的字符 
        s[0]='*';//s[0]='*',s[len+len+2]='\0',防止在while时p[i]越界
        for(int i=2;i<2*len+1;++i){
            if(p[id]+id>i)p[i]=min(p[2*id-i],p[id]+id-i);
            else p[i]=1;
            while(s[i-p[i]] == s[i+p[i]])++p[i];
            if(id+p[id]<i+p[i])id=i;
            if(maxlen<p[i])maxlen=p[i];
        }
        cout<<maxlen-1<<endl;
    }
    return 0;
}

http://blog.csdn.net/xingyeyongheng/article/details/9310555

 

http://www.cnblogs.com/wuyiqi/archive/2012/06/25/2561063.html

http://blog.csdn.net/kk303/article/details/8856263

http://bbezxcy.iteye.com/blog/1452736