Submission #701367

#	Time	Username	Problem	Language	Result	Execution time	Memory
701367		GusterGoose27	Arranging Tickets (JOI17_arranging_tickets)	C++11	85 / 100	616 ms	27260 KiB

arranging_tickets

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef pair<int, int> pii;

const int MAXN = 2e5+10;
int n, m;
ll overall[MAXN];
ll arr[MAXN];
ll req_red[MAXN];
ll r_end[MAXN];
vector<pii> ranges[MAXN]; // right endpoint, index

ll max(ll a, ll b) {
	if (a > b) return a;
	return b;
}

ll num_req(int target) {
	for (int i = 0; i < n; i++) req_red[i] = max(0, arr[i]-target);
	fill(r_end, r_end+n, 0);
	priority_queue<pii> pq;
	ll sub = 0;
	ll num = 0;
	for (pii i: ranges[0]) pq.push(i);
	for (int i = 0; i < n; i++) {
		if (sub < req_red[i]) {
			pii r = pq.top();
			pq.pop();
			ll amt;
			if (r.second > req_red[i]-sub) {
				r.second -= (req_red[i]-sub);
				amt = (req_red[i]-sub);
				pq.push(r);
			}
			else amt = r.second;
			r_end[r.first] += amt;
			sub += amt;
			i--;
			num += amt;
			continue;
		}
		for (pii v: ranges[i+1]) pq.push(v);
		sub -= r_end[i];
	}
	return num;
}

ll solve() {
	ll mn = -1;
	ll mx = 0;
	for (int i = 0; i < n; i++) mx = max(mx, arr[i]);
	mx++;
	// int b = -1;
	// for (int i = mn+1; i < mx; i++) {
	// 	int v = 2*i+num_req(i);
	// 	if (b == -1 || v < b) b = v;
	// }
	// return b;
	while (mx > mn+2) {
		ll cur = (mn+mx)/2;
		ll v1 = num_req(cur);
		ll v2 = num_req(cur+1);
		if (v1 >= v2+2) mn = cur;
		else mx = cur+1;
	}
	return 2*(mn+1)+num_req(mn+1);
}

int main() {
	ios_base::sync_with_stdio(false); cin.tie(NULL);
	cin >> n >> m;
	n--;
	for (int i = 0; i < m; i++) {
		int a, b, c; cin >> a >> b >> c;
		a--; b--;
		if (a > b) swap(a, b);
		ranges[a].push_back(pii(b-1, c));
		overall[a] += c;
		overall[b] -= c;
	}
	for (int i = 0; i < n; i++) {
		overall[i+1] += overall[i];
	}
	for (int i = 0; i < n; i++) {
		arr[i] = (overall[i]+1)/2;
	}
	ll ans = solve();
	for (int i = 0; i < n; i++) arr[i] = overall[i]/2;
	ans = min(ans, solve()+1);
	cout << ans << "\n";
}

• Subtask 1: 10 / 10
• Subtask 2: 35 / 35
• Subtask 3: 20 / 20
• Subtask 4: 20 / 20
• Subtask 5: 0 / 15