ABC140B - Buffet

問題：B - Buffet

#include <iostream>
#include <vector>
using namespace std;

#define REP(i, n) for (int i = 0; i < (n); ++i)

int main(void) {
    int n, ans = 0;

    cin.tie(0);
    ios::sync_with_stdio(false);
    cin >> n;
    vector<int> a(n), b(n), c(n);
    REP(i, n) {
        cin >> a[i];
        a[i]--;
    }
    REP(i, n) {
        cin >> b[i];
    }
    REP(i, n - 1) {
        cin >> c[i];
    }
    REP(i, n) {
        ans += b[a[i]];
        if (0 < i && a[i] == a[i - 1] + 1) {
            ans += c[a[i - 1]];
        }
    }

    cout << ans << "\n";
    return 0;
}