BZOJ 2084「POI2010」Antisymmetry【Manacher】

以前写的代码

#include <cmath>
#include <cstdio>
#include <cstring>
#include <iostream>
#include <algorithm>
#define SG string
#define DB double
#define LL long long
#define Fp(A,B,C,D) for(A=B;A<=C;A+=D)
#define Fm(A,B,C,D) for(A=B;A>=C;A-=D)
#define Clear(A) memset(A,0,sizeof(A))
#define Copy(A,B) memcpy(A,B,sizeof(B))
using namespace std;
const LL Max=5e5+5;
const LL Mod=1e9+7;
const LL Inf=1e18;
LL N,Mid,Len,Lst,Ans,R[Max<<1],Pal[Max<<1];
inline LL Read(){
	LL X=0;char CH=getchar();bool F=0;
	while(CH>'9'||CH<'0'){if(CH=='-')F=1;CH=getchar();}
	while(CH>='0'&&CH<='9'){X=(X<<1)+(X<<3)+CH-'0';CH=getchar();}
	return F?-X:X;
}
inline void Write(LL X){
	if(X<0)X=-X,putchar('-');
	if(X>9)Write(X/10);
	putchar(X%10+48);
}
int main(){
	LL I,J,K;
	N=Read();Pal[0]=Inf-1;
	Fp(I,1,N,1){
		Pal[++Len]=Inf;
		Pal[++Len]=getchar()-'0';
	}Pal[++Len]=Inf;
	Fp(I,1,Len-1,1){
		if(I<Lst){
			R[I]=min(R[(Mid<<1)-I],Lst-I);
		} else {
			R[I]=1;
		}
		while(true){
			if((Pal[I+R[I]]!=Pal[I-R[I]]&&Pal[I+R[I]]+Pal[I-R[I]]==1)||Pal[I+R[I]]==Inf){
				R[I]++;
			} else {
				break;
			}
		}
		if(Lst<I+R[I]&&(I&1)){
			Lst=I+R[I];
			Mid=I;
		}
		if(I&1){
			Ans+=(R[I]-1)>>1;
		}
	}Write(Ans);
	return 0;
}