# NOIP2019_Day1T2_括号树

\[\LARGE ---咕咕咕咕咕！--- \]

真正的题解——转载Inkyo巨佬%%%

代码：

---

贴一张代码好了QAQ

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int N = 500010;
int n;
char a[N]; int fa[N];
int head[N], nxt[N << 1], ver[N << 1], tot;
int sta[N], top;
ll offer[N], sum[N], ans;

void add(int u, int v) {
    ver[++tot] = v; nxt[tot] = head[u]; head[u] = tot;
}

void dfs(int now) {
    if (a[now] == '(') {
        sta[++top] = now;
        offer[now] = 0;
        sum[now] = sum[fa[now]];
        for (int i = head[now]; i; i = nxt[i]) {
            int son = ver[i];
            dfs(son);
        }
        top--;
    } else {
        if (top == 0) {
            offer[now] = 0;
            sum[now] = sum[fa[now]];
            for (int i = head[now]; i; i = nxt[i]) {
                int son = ver[i];
                dfs(son);
            }
        } else {
            int match = sta[top]; top--;
            if (a[fa[match]] == ')') {
                offer[now] = offer[fa[match]] + 1;
                sum[now] = sum[fa[now]] + offer[now];
            } else {
                offer[now] = 1;
                sum[now] = sum[fa[now]] + 1;
            }
            for (int i = head[now]; i; i = nxt[i]) {
                int son = ver[i];
                dfs(son);
            }
            sta[++top] = match;
        }
    }
    return;
}

int main() {
    scanf("%d", &n);
    scanf("%s", a + 1);
    for (int i = 2; i <= n; i++) {
        scanf("%d", &fa[i]);
        add(fa[i], i);
    }
    dfs(1);
    for (int i = 1; i <= n; i++) {
        ans = ans xor (i * sum[i]);
    }
    printf("%lld\n", ans);
    return 0;
}