题目

题解：

#include <bits/stdc++.h>
using namespace std;
#define int long long
#define pb push_back
#define fi first
#define se second
#define lson p << 1
#define rson p << 1 | 1
#define ll long long
#define pii pair<int, int>
#define ld long double
const int maxn = 1e6 + 5, inf = 1e18, maxm = 4e4 + 5, base = 37;
const int N = 1e5 + 5;
const int mod = 1e9 + 7;
// const int mod = 998244353;
// const __int128 mod = 212370440130137957LL;
int n, m;

//long long ? maxn ? n? m?
void solve(){
    ll res = 0;
    int k, w;
	int x;
    cin >> n >> w;
	// vector<int> a(n + 1);
	// for(int i = 1; i <= n; i++){
	// 	cin >> a[i];
	// }
	vector<int> p(n + 1), dep(n + 1), s(n + 1), c(n + 1), cnt(n + 1), siz(n + 1);
	vector<vector<int>> G(n + 1);
	for(int i = 2; i <= n; i++){
		int x;
		cin >> x;
		p[i] = x;
		G[x].pb(i);
	}
	p[1] = 1;
	auto dfs = [&](auto self, int u) -> void {
		siz[u] = 1;
		for(auto v : G[u]){
			dep[v] = dep[u] + 1;
			self(self, v);
			siz[u] += siz[v];
		}
	};
	dfs(dfs, 1);
	for(int i = 1; i <= n; i++){
		int j = i % n + 1;
		cnt[i] = dep[i] + dep[j] - 2 * dep[p[j]];//dis(i, i+1)有多少条边
		// cout << i << ' ' << cnt[i] << '\n';
	}
	int sum = 0;
	int cnt_cer = 0;//多少个dis的值是确定的
	res = n * w;
	for(int i = 1; i < n; i++){
		int x, y;
		cin >> x >> y;
		sum += y;
		auto work = [&](int x) -> void {
			c[x]++;
			s[x] += y;
			if(c[x] == cnt[x]){
				res += s[x] - (w - (sum - s[x]));
				// cout << x << ' ' << res << '\n';
				cnt_cer++;
			}
		};
		work(x - 1);
		work(x + siz[x] - 1);
		int tmp = cnt_cer;
		if(c[x - 1] == cnt[x - 1]) tmp--;
		if(c[x + siz[x] - 1] == cnt[x + siz[x] - 1]) tmp--;
		res -= (n - tmp - 2) * y;
		cout << res << ' ';
	}
	cout << '\n';
}
    
signed main(){
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout << fixed << setprecision(9);
    
    int T = 1;
    cin >> T;
    while (T--){
        solve();
    }
    return 0;
}