Submission #55282

#	Time	Username	Problem	Language	Result	Execution time	Memory
55282		ksun48	Cultivation (JOI17_cultivation)	C++14	35 / 100	2079 ms	764 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<LL> tried;
void tryxfast(LL x){
	if(x < 0 || tried.find(x) != tried.end()){
		return;
	}

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

	vector<LL> pos;
	vector<LL> ups;
	vector<LL> downs;
	vector<LL> totals;

	multiset<LL> grass;
	grass.insert(-1);
	grass.insert(c);
	multiset<LL> diffs;
	diffs.insert(c+1);
	for(auto tt : events){
		for(pair<LL,LL> event : tt.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));
			}
		}
		pos.push_back(tt.first);
		totals.push_back( *(--diffs.end()) );
		ups.push_back( *(++grass.begin()) - 0 );
		downs.push_back( c-1 - *(--(--grass.end())) );
	}
	for(int i = 0; i < totals.size(); i++){
		if(totals[i] == c+1){
			totals[i] = INF;
		}
	}
	// two pointers: 
	int j = 0;
	multiset<LL> upset;
	multiset<LL> downset;
	multiset<LL> totalset;
	for(int i = 0; i < pos.size(); i++){
		while(j < pos.size() && pos[j] <= pos[i] + r - 1){
			upset.insert(ups[j]);
			downset.insert(downs[j]);
			totalset.insert(totals[j]);
			j++;
		}
		best = min(best, max(*(--upset.end()) + *(--downset.end()), *(--totalset.end()) - 1) + x);
		upset.erase(upset.find(ups[i]));
		downset.erase(downset.find(downs[i]));
		totalset.erase(totalset.find(totals[i]));
	}
}
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++){
			tryxfast(seeds[i].first + r-1 - seeds[j].first);
			tryxfast(seeds[i].first -   1 - seeds[j].first);
		}
	}		
	cout << best << '\n';
}

Compilation message (stderr)

cultivation.cpp: In function 'void tryxfast(LL)':
cultivation.cpp:57:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i = 0; i < totals.size(); i++){
                 ~~^~~~~~~~~~~~~~~
cultivation.cpp:67:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i = 0; i < pos.size(); i++){
                 ~~^~~~~~~~~~~~
cultivation.cpp:68:11: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   while(j < pos.size() && pos[j] <= pos[i] + r - 1){
         ~~^~~~~~~~~~~~
cultivation.cpp: In function 'void tryx(LL)':
cultivation.cpp:98:24: 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: 0 / 10
• Subtask 3: 0 / 15
• Subtask 4: 30 / 30
• Subtask 5: 0 / 20
• Subtask 6: 0 / 20