Submission #742119

#	Time	Username	Problem	Language	Result	Execution time	Memory
742119		siewjh	Harbingers (CEOI09_harbingers)	C++17	70 / 100	172 ms	65536 KiB

harbingers

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
const int MAXN = 100'005;
vector<pair<int, ll>> adj[MAXN];
ll prep[MAXN], tim[MAXN], dp[MAXN], dist = 0;
struct line{
	ll m, c;
	ll eval(ll x){
		return m * x + c;
	}
};
deque<line> dq;
vector<line> changes[MAXN];
ld poi(line a, line b) {
	return (ld)(a.c - b.c) / (b.m - a.m);
}
void insert(line a, int ind) {
	while (dq.size() >= 2 && poi(dq.back(), a) <= poi(dq.back(), dq[dq.size() - 2])) {
		changes[ind].push_back(dq.back());
		dq.pop_back();
	}
	dq.push_back(a);
}
ll query(ll x){
	if (dq.empty()) return 0;
	int l = 0, r = dq.size() - 2, ans = dq.size() - 1;
	while (l <= r){
		int m = (l + r) >> 1;
		if (dq[m].eval(x) <= dq[m + 1].eval(x)){
			ans = m;
			r = m - 1;
		}
		else l = m + 1;
	}
	return dq[ans].eval(x);
}
void rollback(int ind){
	dq.pop_back();
	for (int i = changes[ind].size() - 1; i >= 0; i--) dq.push_back(changes[ind][i]);
	changes[ind].clear();
}
void dfs(int x, int par){
	if (x == 1) dp[x] = 0;
	else dp[x] = prep[x] + dist * tim[x] + query(tim[x]);
	insert({-dist, dp[x]}, x);
	for (auto nxt : adj[x]){
		int nn = nxt.first; ll nd = nxt.second;
		if (nn == par) continue;
		dist += nd;
		dfs(nn, x);
		dist -= nd;
	}
	rollback(x);
}
int main(){
	ios_base::sync_with_stdio(false);
	cin.tie(0); cout.tie(0);
	int nodes; cin >> nodes;
	for (int i = 1; i < nodes; i++){
		int a, b; ll d; cin >> a >> b >> d;
		adj[a].push_back({b, d});
		adj[b].push_back({a, d});
	}
	for (int i = 2; i <= nodes; i++) cin >> prep[i] >> tim[i];
	dfs(1, -1);
	for (int i = 2; i <= nodes; i++) cout << dp[i] << ' ';
}

• Subtask 1: 70 / 100