参考博客:Manacher算法——最长回文子串
Manacher算法的模板,写得比较简洁
作为一个模板,还是不错的
#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
const int maxn=;
int tst,f[maxn];
char a[maxn],s[maxn];
int Manacher(){
int n=,res=,maxR=,pos=;
for (int i=;a[i];i++) s[++n]='#',s[++n]=a[i];s[++n]='#';
for (int i=;i<=n;i++){
f[i]=i<maxR?min(f[pos*-i],maxR-i+):;
while (i-f[i]>&&i+f[i]<=n&&s[i-f[i]]==s[i+f[i]]) f[i]++;
if (i+f[i]->maxR) maxR=i+f[i]-,pos=i;
res=max(res,f[i]-);
}
return res;
}
int main(){
scanf("%d",&tst);
for (int i=;i<=tst;i++) scanf("%s",a),printf("%d\n",Manacher());
return ;
}