点个关注吧

#include <iostream>
#include <vector>
using namespace std;
int main(){
    freopen("game.in","r",stdin);
    freopen("game.out","w",stdout);
    int n;
    string s;
    cin >> n >> s;
    s="?"+s;
    vector<int> v1(n+1,0),v2(n+1,0);
    long long ans=0;
    for (int i=1;i<=n;++i){
        int j=i;
        while (j && s[j-1]!=s[i]){
            j=v1[j-1];
        }
        if (j){
            v1[i]=j-1;
        }
        if (v1[i]){
            v2[i]=v2[v1[i]-1]+1;
        }
        ans+=v2[i];
    }
    cout<<ans<<endl;
    fclose(stdin);
    fclose(stdout);
    return 0;
}