poj3974 Palindrome 字符串

来源：互联网发布：iphone同步软件编辑：程序博客网时间：2024/05/16 17:06

这个可以借鉴这篇博客http://blog.csdn.net/u013508213/article/details/29597201

#include <algorithm>#include <cstring>#include <cstdio>#include <iostream>#include <cmath>using namespace std;#define maxn 1100000char st[maxn],play[maxn<<1];int p[maxn<<1],len,cas;void solve(){    cas++;    int len=strlen(st);    memset(play,'#',sizeof(play));    for(int i=0;i<len;i++)    {        play[(i+1)<<1]=st[i];    }    play[0]='?';    len=(len+1)<<1;    play[len]='*';    int id=0,maxl=0,maxid=0;    for(int i=0;i<len;i++)    {        if(i<maxid)        {            p[i]=min(p[2*id-i],maxid-i);        }        else        {            p[i]=1;        }        while(play[i-p[i]]==play[i+p[i]])        {            p[i]++;        }        if(p[i]-1>maxl)        {            maxl=p[i]-1;        }        if(p[i]+i>maxid)        {            maxid=i+p[i];            id=i;        }    }    printf("Case %d: %d\n",cas,maxl);}int main(){    while(1)    {        scanf("%s",st);        if (strcmp(st,"END")==0) break;        solve();    }    return 0;}

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