Submission #55273

#	Time	Username	Problem	Language	Result	Execution time	Memory
55273		ksun48	Cultivation (JOI17_cultivation)	C++14	60 / 100	2020 ms	1044 KiB

cultivation

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

LL r, c, n;
vector<pair<LL,LL> > seeds;
const LL INF = 2100100100;
LL best = INF;
set<pair<LL,LL> > tried;
void tryxwithstart(LL x, LL startx){
	if(x < 0 || tried.find({x,startx}) != tried.end()){
		return;
	}
	LL endx = startx + r - 1;
	// insert z.second at time z.first
	// delete at time z.first + x + 1


	map<LL, vector<pair<LL, LL> > > events;
	for(pair<LL,LL> z : seeds){
		if(z.first + x < startx || z.first > endx) continue;
		events[max(z.first, startx)].push_back({0, z.second}); // ins
		events[min(z.first + x, endx) + 1].push_back({1, z.second}); // del
	}

	LL maxup = 0;
	LL maxdown = 0;
	LL maxtot = 0;

	multiset<LL> grass;
	grass.insert(-1);
	grass.insert(c);
	multiset<LL> diffs;
	diffs.insert(c+1);
	for(auto x : events){
		for(pair<LL,LL> event : x.second){
			LL a = event.second;
			if(event.first == 0){
				grass.insert(a);
			}
			LL a1 = *(--grass.find(a));
			LL a2 = *(++grass.find(a));
			if(event.first == 0){
				diffs.erase(diffs.find(a2-a1));
				diffs.insert(a-a1);
				diffs.insert(a2-a);
			} else if(event.first == 1){
				diffs.erase(diffs.find(a-a1));
				diffs.erase(diffs.find(a2-a));
				diffs.insert(a2-a1);
			}
			if(event.first == 1){
				grass.erase(grass.find(a));
			}
		}
		if(x.first > endx){
			break;
		}
		maxtot = max(maxtot, *(--diffs.end()) );
		maxup = max(maxup, *(++grass.begin()) - 0);
		maxdown = max(maxdown, c-1 - *(--(--grass.end())) );
	}
	if(maxtot == c + 1){
		return;
	}
	best = min(best, max(maxup + maxdown, maxtot - 1) + x);
}
void tryx(LL x){
	vector<LL> stuff[r + x];
	for(pair<LL,LL> z : seeds){
		for(LL j = 0; j <= x; j++){
			stuff[j + z.first].push_back(z.second);
		}
	}
	vector<LL> up(r+x, 0);
	vector<LL> down(r+x, 0);
	vector<LL> tot(r+x, 0);
	for(LL j = 0; j < r+x; j++){
		vector<LL> grass = stuff[j];
		sort(grass.begin(), grass.end());
		if(grass.size() == 0){
			up[j] = down[j] = tot[j] = INF;
		} else {
			up[j] = grass[0] - 0;
			down[j] = c-1 - grass[grass.size()-1];
			for(LL i = 0; i + 1 < grass.size(); i++){
				tot[j] = max(tot[j], grass[i+1] - grass[i] - 1);
			}
		}
	}
	for(LL j = 0; j <= x; j++){
		LL maxup = 0;
		LL maxdown = 0;
		LL maxtot = 0;
		for(LL i = j; i < j + r; i++){
			maxup = max(maxup, up[i]);
			maxdown = max(maxdown, down[i]);
			maxtot = max(maxtot, tot[i]);
		}
		best = min(best, max(maxup + maxdown, maxtot) + x);
	}
}
int main(){	
	cin >> r >> c >> n;
	for(LL i = 0; i < n; i++){
		LL s, e;
		cin >> s >> e;
		s--; e--;
		seeds.push_back({s,e});
	}
	sort(seeds.begin(), seeds.end());
	if(r <= 40){
		for(LL j = 0; j <= 2*r; j++){
			tryx(j);
		}
	} else {	
		for(int i = 0; i < n; i++){
			for(int j = 0; j < n; j++){
				tryxwithstart(seeds[i].first + r-1 - seeds[j].first, seeds[i].first);
			}
			for(int j = 0; j < n; j++){
				for(int k = 0; k < n; k++){
					tryxwithstart(seeds[j].first - 1 - seeds[k].first, seeds[i].first);
				}
			}
		}		
	}
	cout << best << '\n';
}

Compilation message (stderr)

cultivation.cpp: In function 'void tryx(LL)':
cultivation.cpp:86:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    for(LL i = 0; i + 1 < grass.size(); i++){
                  ~~~~~~^~~~~~~~~~~~~~

• Subtask 1: 5 / 5
• Subtask 2: 10 / 10
• Subtask 3: 15 / 15
• Subtask 4: 30 / 30
• Subtask 5: 0 / 20
• Subtask 6: 0 / 20