poj 3974 Palindrome (最长回文字串，manacher裸题)

 1#include <cstdio>
 2#include <cstring>
 3#include <iostream>
 4#include <algorithm>
 5#include <vector>
 6#include <queue>
 7#include <set>
 8#include <map>
 9#include <string>
10#include <cmath>
11#include <cstdlib>
12#include <ctime>
13#define fst first
14#define sec second
15#define lson l,m,rt<<1
16#define rson m+1,r,rt<<1|1
17#define ms(a,x) memset(a,x,sizeof(a))
18typedef long long LL;
19#define pi pair < int ,int >
20#define MP make_pair

1using namespace std;
2const double eps = 1E-8;
3const int dx4[4]={1,0,0,-1};
4const int dy4[4]={0,-1,1,0};
5const int inf = 0x3f3f3f3f;
6const int N=2E6+7;
7char st[2*N];
8int p[2*N];

1int manacher(char *s)
2{
3    int len = strlen(s);
4    for ( int i = len ; i >= 0 ; i-- )
5    {
6	s[i+i+2]=s[i];
7	s[i+i+1]='#';
8    }
9    s[0]='$';

1    for ( int i = 2 ; i < 2*len+1 ; i++)
2    {
3	if (id+p[id]>i) p[i] = min(p[2*id-i],id+p[id]-i);
4	else p[i] = 1;

 1	while (s[i+p[i]]==s[i-p[i]]) p[i]++;
 2	if (id+p[id]<i+p[i]) id =  i;
 3	if (p[i]>maxlen) maxlen = p[i];
 4    }
 5    return maxlen-1;
 6}
 7int main()
 8{
 9	#ifndef  ONLINE_JUDGE 
10	freopen("code/in.txt","r",stdin);
11  #endif
12	int cas = 0 ;
13	while (scanf("%s",st)!=EOF)
14	{
15	    if (st[0]=='E'&&st[1]=='N'&&st[2]=='D') break;
16	    printf("Case %d: %d\n",++cas,manacher(st));

1  #ifndef ONLINE_JUDGE  
2  fclose(stdin);
3  #endif
4    return 0;
5}