最后一行改了之后0分
```
#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#define N 1100005
#define mod 19930726
#define ll long long
#define int ll
using namespace std;
char s[N<<1],a[N<<1];
int p[N],n,le,k,cnt[N],ans=1,tot;
void read(){
scanf("%s",a+1);
//n=strlen(a);
s[0]='~',s[1]='#';
for(int i=1;i<=le;i++)s[i*2-1]='#',s[i*2]=a[i];
le=le*2+1,s[le]='#';
}
void mnc(){
read();
int maxr=0,mid=0;
for(int i=1;i<=le;i++){
if(i<maxr)p[i]=min(maxr-i,p[mid*2-i]);
else p[i]=1;
for(;s[p[i]+i]==s[i-p[i]];++p[i]);
if(p[i]+i>maxr)maxr=p[i]+i,mid=i;
if((p[i]-1)%2)cnt[p[i]-1]++;
}
}
ll qpow(int x,int y){
if(x==1)return 1;
ll ans=1;
while(y) {
if(y&1)ans=(ans*x)%mod;
x=(x*x)%mod;
y>>=1;
}
return ans;
}
signed main(){
scanf("%lld%lld",&n,&k);
le=n;
mnc();
for(int i=n;i>=1;i--){
if(!(i&1))continue;
tot+=cnt[i];
if(k<tot){
ans=(ans*qpow(i,k))%mod;
k-=tot;
break;
}
else{
ans=(ans*qpow(i,tot))%mod;
k-=tot;
}
}
if(k>0)printf("-1");
else printf("%lld",ans);
return 0;
}
```
by 黑影洞人 @ 2021-08-02 15:05:15