Submission #638175

#	Time	Username	Problem	Language	Result	Execution time	Memory
638175		blue	Catfish Farm (IOI22_fish)	C++17	12 / 100	1101 ms	60236 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];
vll tot(1 + maxN, 0);
 
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 invhtwt(int i, int h)
{
	return tot[i] - htwt(i, h-1);
}
 
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]});
		tot[X[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]);
			}
		}
 
 
		ll Dmx = 0;
		ll Did = -1;
 
 
		for(int i = 0; i < sz(fish[r]); i++)
		{
			ll basic = 0;
 
			ll Bcatch = 0;
			int Bk = -1;
 
			ll constD = -invhtwt(r-1, fish[r][i].first) + tot[r-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);
 
			//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));
			}
 
			// 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;
				
			// 	// 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;
			// 	// }
			// 	// if(j >= 1)
			// 	// 	ext -= fishpref[r-1][j-1];
			// 	// ll ext = -invhtwt(r-1, fish[r][i].first);
 
			// 	selfmax(inc[r][i], inc[r-1][j] - (j >= 1 ? fishpref[r-1][j-1] : 0) + constD);
			// 	selfmax(dec[r][i], inc[r-1][j] - (j >= 1 ? fishpref[r-1][j-1] : 0) + constD);
			// }
			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;

 
		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--;
 				bestval = max(bestval, dec[r-1][j] + tot[r] - (i >= 1 ? fishpref[r][i-1] : 0) - invhtwt(r, fish[r-1][j].first));
 			}

 			selfmax(dec[r][i], bestval);
			// 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;
			// 	// }
 
			// 	// ll ext = tot[r];
			// 	// if(i >= 1)
			// 	// 	ext -= fishpref[r][i-1];
			// 	// ext -= invhtwt(r, fish[r-1][j].first);
 
			// 	selfmax(dec[r][i], );
			// 	// 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 2: 0 / 6
• Subtask 3: 9 / 9
• Subtask 4: 0 / 14
• Subtask 5: 0 / 21
• Subtask 6: 0 / 17
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