CF706C Hard problem (状态机dp)

#include<iostream>
#include<cstring>
#include<cstdio>
#include<map>
#include<algorithm>
#define ull unsigned long long
using namespace std;
typedef long long ll;
const int N=1e5+10;
string s[N],s1[N];
ll p[N];
ll f[N][2];
int main(){
    int i;
    int n;
    cin>>n;
    for(i=1;i<=n;i++){
        scanf("%lld",&p[i]);
    }
    for(i=1;i<=n;i++){
        cin>>s[i];
        s1[i]=s[i];
        reverse(s1[i].begin(),s1[i].end());
    }
    for(i=1;i<=n;i++){
        for(int j=0;j<=1;j++)
            f[i][j]=1e18;
    }
    f[1][0]=0;
    f[1][1]=p[1];
    for(i=2;i<=n;i++){
        if(s[i]>=s[i-1])
            f[i][0]=min(f[i][0],f[i-1][0]);
        if(s[i]>=s1[i-1])
            f[i][0]=min(f[i][0],f[i-1][1]);
        if(s1[i]>=s[i-1])
            f[i][1]=min(f[i][1],f[i-1][0]+p[i]);
        if(s1[i]>=s1[i-1])
            f[i][1]=min(f[i][1],f[i-1][1]+p[i]);
    }
    ll ans=min(f[n][1],f[n][0]);
    if(ans==1e18)
    cout<<-1<<endl;
    else
        cout<<ans<<endl;

}