Submission #834682

#	Time	Username	Problem	Language	Result	Execution time	Memory
834682		happypotato	Hiring (IOI09_hiring)	C++17	100 / 100	442 ms	21436 KiB

hiring

#include <bits/stdc++.h>
using namespace std;
#define int long long
#define pii pair<int, int>
#define ff first
#define ss second
#define pb push_back
const int mxN = 2e4;
pii seg[4 * mxN]; // {workers, cost}
vector<int> freq[mxN + 1];
void build(int l = 1, int r = mxN, int idx = 1) {
	if (l == r) {
		seg[idx] = {0, 0};
		return;
	}
	int mid = (l + r) >> 1;
	build(l, mid, (idx << 1));
	build(mid + 1, r, (idx << 1) | 1);
	seg[idx] = {0, 0};
}
void update(int pos, int l = 1, int r = mxN, int idx = 1) {
	if (l == r) {
		seg[idx].ff++;
		seg[idx].ss += pos;
		return;
	}
	int mid = (l + r) >> 1;
	if (pos <= mid) update(pos, l, mid, (idx << 1));
	else update(pos, mid + 1, r, (idx << 1) | 1);
	seg[idx].ff = seg[(idx << 1)].ff + seg[(idx << 1) | 1].ff;
	seg[idx].ss = seg[(idx << 1)].ss + seg[(idx << 1) | 1].ss;
}
pii query(int tar, int l = 1, int r = mxN, int idx = 1) {
	if (l == r) {
		int res = min(seg[idx].ff, tar / l);
		return {res, res * l};
	}
	int mid = (l + r) >> 1;
	pii res = {0, 0};
	if (seg[(idx << 1)].ss < tar) {
		res = query(tar - seg[(idx << 1)].ss, mid + 1, r, (idx << 1) | 1);
		res.ff += seg[(idx << 1)].ff;
		res.ss += seg[(idx << 1)].ss;
	} else {
		res = query(tar, l, mid, (idx << 1));
	}
	return res;
}
bool cmp(pair<pii, int> &lhs, pair<pii, int> &rhs) {
	// lhs.ff.ff / lhs.ff.ss < rhs.ff.ff / rhs.ff.ss (smaller cost per qualification)
	return lhs.ff.ff * rhs.ff.ss < rhs.ff.ff * lhs.ff.ss;
}
void solve() {
	int n, w;
	cin >> n >> w;
	vector<pair<pii, int>> v(n);
	for (int i = 0; i < n; i++) {
		cin >> v[i].ff.ff >> v[i].ff.ss;
		v[i].ss = i + 1;
	}
	sort(v.begin(), v.end(), cmp);

	// 1st run: find answer
	build();
	pair<pair<int, double>, int> best = {{0, 0}, -1}; // {{workers, cost}, bound}
	for (int i = 0; i < n; i++) {
		update(v[i].ff.ss);
		int allow = w * v[i].ff.ss / v[i].ff.ff;
		pii res = query(allow);
		double cost = res.ss * 1.0 * (v[i].ff.ff * 1.0 / v[i].ff.ss);
		// cerr << res.ff << ' ' << res.ss << ' ' << allow << endl;
		if (res.ff > best.ff.ff || (res.ff == best.ff.ff && cost < best.ff.ss)) {
			best = {{res.ff, cost}, i};
		}
	}
	// 2nd run: find construction
	for (int i = 0; i <= best.ss; i++) {
		freq[v[i].ff.ss].pb(v[i].ss);
	}
	vector<int> ans;
	for (int i = 1; i <= mxN; i++) {
		if (!best.ff.ff) break;
		for (int &x : freq[i]) {
			ans.pb(x);
			best.ff.ff--;
			if (!best.ff.ff) break;
		}
	}
	sort(ans.begin(), ans.end());
	
	cout << ans.size() << endl;
	for (int &x : ans) cout << x << endl;
}
int32_t main() {
	ios::sync_with_stdio(0); cin.tie(0);
	solve();
}

• Subtask 1: 30 / 30
• Subtask 2: 28 / 28
• Subtask 3: 6 / 6
• Subtask 4: 6 / 6
• Subtask 5: 6 / 6
• Subtask 6: 6 / 6
• Subtask 7: 6 / 6
• Subtask 8: 6 / 6
• Subtask 9: 6 / 6