Submission #652463

#	Time	Username	Problem	Language	Result	Execution time	Memory
652463		blue	Catfish Farm (IOI22_fish)	C++17	100 / 100	316 ms	68660 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())
 
void selfmax(ll& a, ll b)
{
	a = max(a, b);
}
 
const int maxN = 100'000;
 
vpll fish[1 + maxN];
vll fishpref[1 + maxN];
vll tot(1 + maxN, 0);
 
ll max_weights(int N, int M, vi X, vi Y, vi W)
{
	vvll sm(2, vll(N, 0));
	for(int j = 0; j < M; j++)
		if(X[j] < 2)
			sm[X[j]][Y[j]] += W[j];
 
	if(N == 2)
	{
		return max(sm[0][0] + sm[0][1], sm[1][0] + sm[1][1]);
	}

 
	int xmx = 0;
	for(int j = 0; j < M; j++)
	{
		X[j]++;
		xmx = max(xmx, X[j] + 2);
		Y[j]++;
	}
	xmx = min(xmx, N);
 
	// cerr << "xmx = " << xmx << '\n';
 
	vpll fish[1+N];
	ll* fishpref[1+N];
 
	vpii fishbyY[1+N];
 
	for(int j = 0; j < M; j++)
	{
		// fish[X[j]].push_back({Y[j], W[j]});
		fishbyY[Y[j]].push_back({X[j], W[j]});
		tot[X[j]] += W[j];
	}
 
	for(int y = 0; y <= N; y++)
		for(pii z : fishbyY[y])
			fish[z.first].push_back({y, z.second});
 
	for(int r = 1; r <= xmx; 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] = new ll[sz(fish[r])];
		for(int i = 0; i < sz(fish[r]); i++)
		{
			fishpref[r][i] = (i == 0 ? 0 : fishpref[r][i-1]) + fish[r][i].second;
		}
	}
 
	fish[0] = vpll{{0, 0}};
	fishpref[0] = new ll[1];
	fishpref[0][0] = 0;
 
	// vvll inc(1+N), dec(1+N);
	ll* inc[1+N];
	ll* dec[1+N];
	ll* incpref[1+N];
	ll* decpref[1+N]; //pref inc dec mx
	inc[0] = new ll[1];
	inc[0][0] = 0;

	dec[0] = new ll[1];
	dec[0][0] = 0;
 
 	ll res = 0;
	// cerr << "done\n";
 
	for(int r = 1; r <= xmx; r++)
	{
		incpref[r-1] = new ll[sz(fish[r-1])];
		decpref[r-1] = new ll[sz(fish[r-1])];

		incpref[r-1][0] = decpref[r-1][0] = 0;

		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);
		inc[r] = new ll[sz(fish[r])];
		dec[r] = new ll[sz(fish[r])];
		for(int i = 0; i < sz(fish[r]); i++)
			inc[r][i] = dec[r][i] = 0;
 
 
 
 
 
 
		vll Csuff;
		if(r >= 2)
		{
			Csuff = vll(sz(fish[r-2]));
 
			int pi = sz(fish[r-1])-1;
			ll pwt = tot[r-1];
 
			for(int j = sz(fish[r-2])-1; j >= 0; j--)
			{
				while(pi >= 0 && fish[r-1][pi].first > fish[r-2][j].first - 1)
				{
					pwt -= fish[r-1][pi].second;
					pi--;
				}
 
				// Csuff[j] = max(inc[r-2][j], dec[r-2][j]) + htwt(r-1, fish[r-2][j].first - 1);
				Csuff[j] = max(inc[r-2][j], dec[r-2][j]) + pwt;
				if(j+1 < sz(fish[r-2]))
					selfmax(Csuff[j], Csuff[j+1]);
			}
		}
 
 
		ll Dmx = 0;
		ll Did = -1;
 
		int ppi = -1;
 		int qi = -1;
 		ll qwt = 0;
 
		for(int i = 0; i < sz(fish[r]); i++)
		{
			ll basic = 0;
 
			ll Bcatch = 0;
			// int Bk = -1;

			ll oldqwt = qwt;
 
			while(qi+1 < sz(fish[r-1]) && fish[r-1][qi+1].first <= fish[r][i].first - 1)
			{
				qi++;
				qwt += fish[r-1][qi].second;
			}
			ll prevpwt = qwt;
 
			ll constD = -(tot[r-1] - prevpwt) + tot[r-1];
 
			if(r >= 2)
			{
				//A
				selfmax(basic, max(inc[r-2][0], dec[r-2][0]) + prevpwt);
 
 
 
 
 				while(ppi+1 < sz(fish[r-2]) && fish[r-2][ppi+1].first <= fish[r][i].first)
 					ppi++;
				int ploci = ppi;
 
				// 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;
				// }
				Bcatch = qwt;
				// assert(Bcatch == qwt);
				// assert(Bk == qi);
				selfmax(basic, Bcatch + max(incpref[r-2][ploci], decpref[r-2][ploci]));
	
				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);
 
			//type D transition
 
			while(Did+1 < sz(fish[r-1]) && fish[r-1][Did+1].first <= fish[r][i].first)
			{
				Did++;
				Dmx = max(Dmx, inc[r-1][Did] - (Did >= 1 ? fishpref[r-1][Did-1] : 0));
			}
 
			selfmax(inc[r][i], Dmx + constD);
			selfmax(dec[r][i], Dmx + constD);
 
		}
 
		int j = sz(fish[r-1]);
		ll bestval = -1'000'000'000'000'000'000LL;
 
		int ri = sz(fish[r]);
		ll rwt = 0;
 
 
		for(int i = sz(fish[r])-1; i >= 0; i--)
		{
 			while(j-1 >= 0 && fish[r-1][j-1].first > fish[r][i].first)
 			{
 				j--;
 				while(ri-1 >= 0 && fish[r][ri-1].first >= fish[r-1][j].first)
 				{
 					ri--;
 					rwt += fish[r][ri].second;
 				}
 				bestval = max(bestval, dec[r-1][j] + tot[r] - rwt);
 			}
 
 			selfmax(dec[r][i], bestval - (i >= 1 ? fishpref[r][i-1] : 0));
		}

		for(int i = 0; i < sz(fish[r]); i++)
			selfmax(res, max(inc[r][i], dec[r][i]));
	}
 
	return res;
}

Compilation message (stderr)

fish.cpp: In function 'll max_weights(int, int, vi, vi, vi)':
fish.cpp:166:7: warning: unused variable 'oldqwt' [-Wunused-variable]
  166 |    ll oldqwt = qwt;
      |       ^~~~~~

• 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