Manacher || Luogu P3805【模板】manacher算法

题面：【模板】manacher算法

代码：

 #include<cstdio>
 #include<cstring>
 #include<iostream>
 #define max(a,b) ((a)>(b)?(a):(b))
 #define min(a,b) ((a)<(b)?(a):(b))
 using namespace std;
 const int maxn=+;
 int len,N,mr,mid,RL[maxn<<],ans=;
 char S[maxn<<],a[maxn];
 inline void Manacher(){
     mr=mid=;
     for(int i=;i<=len;i++){
         if(i<mr) RL[i]=min(RL[(mid<<)-i],mr-i);
         else RL[i]=;
         while(i-RL[i]>=&&i+RL[i]<=len&&
               S[i-RL[i]]==S[i+RL[i]])RL[i]++;
         if(i+RL[i]->mr){
             mr=i+RL[i]-;
             mid=i;
         }
         ans=max(ans,RL[i]-);
     }
     return;
 }
 int main(){
     scanf("%s",a);
     N=strlen(a);
     S[]='$';
     S[len=]='#';
     for(int i=;i<N;i++){
         S[++len]=a[i];
         S[++len]='#';
     }
     Manacher();
     printf("%d\n",ans);
     return ;
 }

---

By:AlenaNuna