Submission #638161

#	Time	Username	Problem	Language	Result	Execution time	Memory
638161		blue	Catfish Farm (IOI22_fish)	C++17	37 / 100	1096 ms	50656 KiB

fish

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

using ll = long long;
using vll = vector<ll>;
using vvll = vector<vll>;
using pii = pair<int, int>;
using vpii = vector<pii>;
using vvpii = vector<vpii>;
using vi = vector<int>;
using vvi = vector<vi>;
using pll = pair<ll, ll>;
using vpll = vector<pll>;
#define sz(x) int(x.size())

const int lg = 18;

void selfmax(ll& a, ll b)
{
	a = max(a, b);
}

const int maxN = 100'000;

vpll fish[1 + maxN];
vll fishpref[1 + maxN];

int maxind(int i, int h)
{
	//return max ind of col i so that corresponding height is <= h
	int b = -1;
	for(int e = lg; e >= 0; e--)
	{
		if(b + (1<<e) < sz(fish[i]) && fish[i][b + (1<<e)].first <= h)
			b += (1<<e);
	}
	return b;
}

ll htwt(int i, int h)
{
	int j = maxind(i, h);
	if(j == -1)
		return 0;
	else
		return fishpref[i][j];
}

ll max_weights(int N, int M, vi X, vi Y, vi W)
{
	for(int j = 0; j < M; j++)
	{
		X[j]++;
		Y[j]++;
	}

	// vpll fish[1+N];
	// vll fishpref[1+N];

	for(int j = 0; j < M; j++)
	{
		fish[X[j]].push_back({Y[j], W[j]});
	}

	for(int r = 1; r <= N; r++)
	{
		fish[r].push_back({N+1, 0});
		sort(fish[r].begin(), fish[r].end());

		if(fish[r][0].first != 1)
		{
			fish[r].insert(fish[r].begin(), {1, 0});
		}

		fishpref[r] = vll(sz(fish[r]));
		for(int i = 0; i < sz(fishpref[r]); i++)
		{
			fishpref[r][i] = (i == 0 ? 0 : fishpref[r][i-1]) + fish[r][i].second;
		}
	}

	fish[0] = vpll{{0, 0}};
	fishpref[0] = vll{0};

	vvll inc(1+N), dec(1+N);
	vvll incpref(1+N), decpref(1+N); //pref inc dec mx
	inc[0] = dec[0] = vll{0};

	// cerr << "done\n";

	for(int r = 1; r <= N; r++)
	{
		incpref[r-1] = inc[r-1];
		decpref[r-1] = dec[r-1];
		for(int i = 1; i < sz(fish[r-1]); i++)
		{
			incpref[r-1][i] = max(incpref[r-1][i-1], inc[r-1][i]);
			decpref[r-1][i] = max(decpref[r-1][i-1], dec[r-1][i]);
		}


		inc[r] = dec[r] = vll(sz(fish[r]), 0);






		vll Csuff;
		if(r >= 2)
		{
			Csuff = vll(sz(fish[r-2]));
			for(int j = sz(fish[r-2])-1; j >= 0; j--)
			{
				Csuff[j] = max(inc[r-2][j], dec[r-2][j]) + htwt(r-1, fish[r-2][j].first - 1);
				if(j+1 < sz(fish[r-2]))
					selfmax(Csuff[j], Csuff[j+1]);
			}
		}

		for(int i = 0; i < sz(fish[r]); i++)
		{
			ll basic = 0;

			ll Bcatch = 0;
			int Bk = -1;

			if(r >= 2)
			{
				//A
				selfmax(basic, max(inc[r-2][0], dec[r-2][0]) + htwt(r-1, fish[r][i].first - 1));





				int ploci = maxind(r-2, fish[r][i].first);

				//B
				/*for(int j = 0; j <= ploci; j++)
				{
					// cerr << "j = " << j << " out of (exc) " << sz(fish[r-2]) << '\n';
					ll medcatch = 0;
					for(int k = 0; k < sz(fish[r-1]); k++)
						if(fish[r-1][k].first <= fish[r][i].first - 1)
							medcatch += fish[r-1][k].second;

					selfmax(basic, max(inc[r-2][j], dec[r-2][j]) + medcatch);
				}*/
				while(Bk+1 < sz(fish[r-1]) && fish[r-1][Bk+1].first <= fish[r][i].first - 1)
				{
					Bk++;
					Bcatch += fish[r-1][Bk].second;
				}
				selfmax(basic, Bcatch + max(incpref[r-2][ploci], decpref[r-2][ploci]));
				// for(int j = 0; j <= ploci; j++)
				// {
				// 	// cerr << "j = " << j << " out of (exc) " << sz(fish[r-2]) << '\n';
					

				// 	// selfmax(basic, max(inc[r-2][j], dec[r-2][j]) + Bcatch);
				// 	selfmax(basic, )
				// }


				//C
				// for(int j = sz(fish[r-2])-1; j > ploci; j--)
				// {
				// 	// cerr << "j = " << j << " out of (exc) " << sz(fish[r-2]) << '\n';
				// 	ll medcatch = 0;
				// 	for(int k = 0; k < sz(fish[r-1]); k++)
				// 		if(fish[r-1][k].first <= fish[r-2][j].first - 1)
				// 			medcatch += fish[r-1][k].second;

				// 	selfmax(basic, max(inc[r-2][j], dec[r-2][j]) + medcatch);
				// }

				if(ploci+1 < sz(fish[r-2]))
				{
					// cerr << ploci << " : " << sz(fish[r-2]) << '\n';
					selfmax(basic, Csuff[ploci+1]);
				}
			}

			selfmax(inc[r][i], basic);
			selfmax(dec[r][i], basic);
			for(int j = 0; j < sz(fish[r-1]) && fish[r-1][j].first <= fish[r][i].first; j++)
			{
				// cerr << "j = " << j << " , " << fish[r-1][j].first-1 << '\n';
				ll ext = 0;
				if(fish[r-1][j].first - 1 <= fish[r][i].first - 1)
				{
					// cerr << "case 1\n";
					for(int k = j; k < sz(fish[r-1]); k++)
					{
						if(fish[r-1][k].first <= fish[r][i].first - 1)
							ext += fish[r-1][k].second;
					}

					selfmax(inc[r][i], inc[r-1][j] + ext);
					selfmax(dec[r][i], inc[r-1][j] + ext);
				}
			}

			for(int j = sz(fish[r-1])-1; j >= 0 && fish[r-1][j].first > fish[r][i].first; j--)
			{
				
				ll ext = 0;
				// cerr << "case 2\n";
				for(int k = i; k < sz(fish[r]); k++)
				{
					if(fish[r][k].first <= fish[r-1][j].first - 1)
						ext += fish[r][k].second;
				}

				selfmax(dec[r][i], dec[r-1][j] + ext);
				// cerr << r << ' ' << fish[r][i].first-1 << " : " << inc[r][i] << ' ' << dec[r][i] << '\n';		
		
			}
		}
	}

	ll res = 0;
	for(vll x : inc)
		for(ll y : x)
			res = max(res, y);
	for(vll x : dec)
		for(ll y : x)
			res = max(res, y);

	return res;
}

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• Subtask 3: 9 / 9
• Subtask 4: 14 / 14
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