Submission #800625

#	Time	Username	Problem	Language	Result	Execution time	Memory
800625		happypotato	Boxes with souvenirs (IOI15_boxes)	C++17	100 / 100	777 ms	342084 KiB

boxes

#include "boxes.h"
#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
int n, k, l;
vector<int> v;
int st1() {
	int ans = 0;
	for (int i = 1; i <= n; i++) ans += min(l, min(v[i], l - v[i]) * 2);
	return ans;
}
int st2() {
	int ans = min(l, min(v[n], l - v[1]) * 2);
	// ???
	cerr << ans << endl;
	return ans;
}
int clear(int lb, int rb) {
	return min(l, min(v[rb], l - v[lb]) * 2);
}
int st5() {
	// idk anymore
	// what was I doing... it is obviously wrong...
	int asc[n + 2], desc[n + 2];
	multiset<int> ms;

	// ascending: min(l, a[rb] * 2) -> only care about rb
	ms.clear(); ms.insert(0);
	asc[0] = 0; asc[n + 1] = 1e18;
	for (int i = 1; i <= n; i++) {
		asc[i] = *ms.begin() + min(l, v[i] * 2);
		ms.insert(asc[i]);
		if (i >= k) ms.erase(ms.find(asc[i - k]));
	}

	// descending: min(l, (l - a[lb]) * 2) -> only care about lb
	ms.clear(); ms.insert(0);
	desc[n + 1] = 0; desc[0] = 1e18;
	for (int i = n; i >= 1; i--) {
		desc[i] = *ms.begin() + min(l, (l - v[i]) * 2);
		ms.insert(desc[i]);
		if (i + k <= n + 1) ms.erase(ms.find(desc[i + k]));
	}

	int ans = 1e18;
	for (int i = 0; i <= n; i++) {
		ans = min(ans, asc[i] + desc[i + 1]);
	}

	return ans;
}

int st6() {
	int asc[n + 2], desc[n + 2];

	// ascending: min(l, a[rb] * 2) -> only care about rb
	asc[0] = 0; asc[n + 1] = 1e18;
	for (int i = 1; i <= k; i++) {
		asc[i] = min(l, v[i] * 2);
	}
	for (int i = k + 1; i <= n; i++) {
		asc[i] = asc[i - k] + min(l, v[i] * 2);
	}

	// descending: min(l, (l - a[lb]) * 2) -> only care about lb
	desc[n + 1] = 0; desc[0] = 1e18;
	for (int i = n; i > n - k; i--) {
		desc[i] = min(l, (l - v[i]) * 2);
	}
	for (int i = n - k; i >= 1; i--) {
		desc[i] = desc[i + k] + min(l, (l - v[i]) * 2);
	}

	int ans = 1e18;
	for (int i = 0; i <= n; i++) {
		ans = min(ans, asc[i] + desc[i + 1]);
	}

	return ans;
}

long long delivery(int32_t N, int32_t K, int32_t L, int32_t p[]) {
	l = L; v.clear(); v.pb(-1);
	for (int i = 0; i < N; i++) if (p[i] > 0) v.pb(p[i]);
	sort(v.begin(), v.end());
	n = (int)(v.size()) - 1; k = min((int)(K), n);
	if (n == 0) return 0;
	return st6();
	throw runtime_error("not yet");
}
#undef int
/*
subtasks 1-3 trivial
subtask 4 should be O(n^2) left-right dp
*/

• Subtask 1: 10 / 10
• Subtask 2: 10 / 10
• Subtask 3: 15 / 15
• Subtask 4: 15 / 15
• Subtask 5: 20 / 20
• Subtask 6: 30 / 30