Submission #666757

#	Time	Username	Problem	Language	Result	Execution time	Memory
666757		flappybird	Catfish Farm (IOI22_fish)	C++17	100 / 100	208 ms	29668 KiB

fish

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

#define MAX 302020
typedef long long ll;
typedef pair<int, int> pii;

ll tdp[MAX]; // full dp
ll bdp[MAX]; // zero dp
ll sum[MAX];

vector<pii> locs[MAX];

struct bit {
	int N;
	bool rev;
	vector<ll> tree;
	bit(int N, bool rev) :N(N + 2), rev(rev) { tree = vector<ll>(N + 3, -1e18); }
	void upd(int i, ll v) {
		if (rev) i = N - i - 1;
		i++;
		while (i <= N) {
			tree[i] = max(tree[i], v);
			i += i & -i;
		}
	}
	ll get(int i) {
		if (rev) i = N - i - 1;
		i++;
		ll ans = -1e18;
		while (i) {
			ans = max(ans, tree[i]);
			i -= i & -i;
		}
		return ans;
	}
};

ll max_weights(int N, int M, vector<int> X, vector<int> Y, vector<int> W) {
	int i;
	for (auto& v : X) v++;
	for (auto& v : Y) v++;
	for (i = 0; i < M; i++) locs[X[i]].emplace_back(Y[i], W[i]);
	for (i = 1; i <= N; i++) if (locs[i].size()) {
		sort(locs[i].begin(), locs[i].end());
		for (auto& [_, v] : locs[i]) sum[i] += v;
	}
	bit fenu(N, false), fend(N, true);
	fenu.upd(0, 0);
	for (i = 0; i <= N; i++) tdp[i] = bdp[i] = -1e18;
	for (i = 1; i <= N; i++) {
		tdp[i] = tdp[i - 1];
		bdp[i] = bdp[i - 1];
		if (i > 2) fend.upd(N + 1, tdp[i - 2]);
		if (i > 1) fenu.upd(0, bdp[i - 1]);
		if (i > 1) fend.upd(N + 1, 0);
		for (auto& [y, w] : locs[i]) fenu.upd(y, fenu.get(y - 1) + w);
		tdp[i] = max(tdp[i], fenu.get(N + 1));
		for (int j = (int)locs[i].size() - 1; j >= 0; j--) {
			ll y = locs[i][j].first;
			ll w = locs[i][j].second;
			fend.upd(y, fend.get(y + 1) + w);
		}
		bdp[i] = max(bdp[i], fend.get(0));
		if (i > 2) tdp[i] = max(tdp[i], sum[i] + tdp[i - 2]);
	}
	ll ans = fend.get(0);
	for (i = 1; i < N; i++) ans = max(ans, tdp[i]);
	for (i = 1; i <= N; i++) ans = max(ans, bdp[i]);
	return ans;
}

• Subtask 1: 3 / 3
• Subtask 2: 6 / 6
• Subtask 3: 9 / 9
• Subtask 4: 14 / 14
• Subtask 5: 21 / 21
• Subtask 6: 17 / 17
• Subtask 7: 14 / 14
• Subtask 8: 16 / 16