제출 #875137

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
875137		MinaRagy06	Arboras (RMI20_arboras)	C++17	0 / 100	40 ms	3668 KiB

arboras

#include <bits/stdc++.h>
using namespace std;
#define ll long long

const int mod = 1e9 + 7;
struct mint {
	int v = 0;
	mint() {}
	mint(int x) {v = x;}
	mint& operator+=(mint b) {
		if ((v += b.v) >= mod) {
			v -= mod;
		}
		return *this;
	}
	mint& operator-=(mint b) {
		if ((v -= b.v) < 0) {
			v += mod;
		}
		return *this;
	}
	friend mint operator+(mint a, mint b) {
		return a += b;
	}
	friend mint operator-(mint a, mint b) {
		return a -= b;
	}
	friend bool operator>(mint a, mint b) {
		return a.v > b.v;
	}
	friend bool operator<(mint a, mint b) {
		return b > a;
	}
	friend ostream& operator<<(ostream &os, mint a) {
		return os << a.v;
	}
};
int main() {
	ios_base::sync_with_stdio(0), cin.tie(0);
	int n;
	cin >> n;
	int p[n]{};
	for (int i = 1; i < n; i++) {
		cin >> p[i];
	}
	int d[n]{};
	for (int i = 1; i < n; i++) {
		cin >> d[i];
	}
	pair<mint, int> dp[n][2]{};
	mint ans = 0;
	for (int i = n - 1; i > 0; i--) {
		if (dp[i][0].first + d[i] > dp[p[i]][1].first) {
			dp[p[i]][1] = {dp[i][0].first + d[i], i};
			if (dp[p[i]][1] > dp[p[i]][0]) swap(dp[p[i]][0], dp[p[i]][1]);
		}
		ans += dp[i][0].first + dp[i][1].first;
	}
	ans += dp[0][0].first + dp[0][1].first;
	cout << (ans.v % mod + mod) % mod << '\n';
	int q;
	cin >> q;
	while (q--) {
		int i, v;
		cin >> i >> v;
		d[i] += v;
		d[i] %= mod;
		mint old = 0, cur = -1;
		while (old.v != cur.v && i != 0) {
			old = cur = dp[p[i]][0].first;
			if (dp[p[i]][0].second == i) {
				swap(dp[p[i]][0], dp[p[i]][1]);
			}
			if (dp[p[i]][1].second == i || dp[i][0].first + d[i] > dp[p[i]][1].first) {
				ans -= dp[p[i]][0].first + dp[p[i]][1].first;
				dp[p[i]][1] = {dp[i][0].first + d[i], i};
				if (dp[p[i]][1] > dp[p[i]][0]) {
					swap(dp[p[i]][0], dp[p[i]][1]);
				}
				cur = dp[p[i]][0].first;
				ans += dp[p[i]][0].first + dp[p[i]][1].first;
			}
			i = p[i];
		}
		cout << (ans.v % mod + mod) % mod << '\n';
	}
	return 0;
}

• Subtask 1: 0 / 11
• Subtask 2: 0 / 13
• Subtask 3: 0 / 31
• Subtask 4: 0 / 45