Fenwick with range updates

const int MAX_N = 1e5;
int n;
ll Mul[MAX_N], Add[MAX_N];

void suf_upd(int pos, ll mul, ll add) {
    while(pos < n) {
        Mul[pos] += mul;
        Add[pos] += add;
        pos |= (pos + 1);
    }
}

void upd(int l, int r, ll add) {
    suf_upd(l, add, -add*(l-1));
    suf_upd(r+1, -add, add*r);
}

ll get(int pos) {
    ll mul = 0, add = 0;
    for(int i = pos; i >= 0; i = (i & (i+1)) - 1) {
        mul += Mul[i];
        add += Add[i];
    }

    return mul * pos + add;
}

ll get(int l, int r) {
    return get(r) - (l > 0 ? get(l-1) : 0);
}

int main() {
    cin >> n;
    for(int i = 0; i < n; i++) {
        int a;
        cin >> a;
        upd(i, i, a);
    }
    int q;
    cin >> q;
    while(q--) {
        char c;
        cin >> c;
        if(c == 'g') {
            int pos;
            cin >> pos;
            cout << get(pos-1, pos-1) << ' ';
        }
        else {
            int l, r, x;
            cin >> l >> r >> x;
            upd(l-1, r-1, x);
        }
    }
}