Submission #558967

#	Time	Username	Problem	Language	Result	Execution time	Memory
558967		blue	The Kingdom of JOIOI (JOI17_joioi)	C++17	100 / 100	3657 ms	86552 KiB

joioi

#include <iostream>
#include <vector>
#include <set>
#include <algorithm>
using namespace std;

#define sz(x) int(x.size())
using vi = vector<int>;
using vvi = vector<vi>;

vvi T;

int lim;

//1 = lo, 2 = hi, 3 = both

bool solve()
{
	int H = sz(T) - 2;
	int W = sz(T[0]) - 2;

	bool works = 1;

	vvi P = T;
	for(int i = 1; i <= H; i++)
	{
		for(int j = 1; j <= W; j++)
		{
			P[i][j] = (P[i-1][j] || P[i][j-1] || (T[i][j] == 1));
			if(P[i][j] && (T[i][j] == 2))
				works = 0;
		}
	}

	return works;
}

int main()
{
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);

	int H, W;
	cin >> H >> W;

	int res = 2'000'000'001;

	int amx = 0, amn = 1'000'000'001;

	vvi A = vvi(1+H+1, vi(1+W+1));
	for(int i = 1; i <= H; i++)
	{
		for(int j = 1; j <= W; j++)
		{
			cin >> A[i][j];

			amx = max(amx, A[i][j]);
			amn = min(amn, A[i][j]);
		}
	}

	T = vvi(1+H+1, vi(1+W+1));

	int lo = 0, hi = 1'000'000'000;
	while(lo != hi)
	{
		lim = (lo+hi)/2;

		bool works = 0;

		bool failed = 0;

		for(int i = 1; i <= H; i++)
		{
			for(int j = 1; j <= W; j++)
			{
				int islo = (A[i][j] - amn) <= lim;
				int ishi = (amx - A[i][j]) <= lim;

				if(islo && ishi)
					T[i][j] = 3;
				else if(islo)
					T[i][j] = 1;
				else if(ishi)
					T[i][j] = 2;
				else
					failed = 1;
			}
		}

		if(failed)
		{
			works = 0;
		}
		else
		{
			works = 0;
			works |= solve();

			for(int i = 1; i <= H; i++)
				reverse(T[i].begin(), T[i].end());

			works |= solve();

			for(int j = 1; j <= W; j++)
				for(int i = 1; 2*i <= H; i++)
					swap(T[i][j], T[H-i+1][j]);

			works |= solve();

			for(int i = 1; i <= H; i++)
				reverse(T[i].begin(), T[i].end());

			works |= solve();
		}

		if(works)
			hi = lim;
		else
			lo = lim+1;

	}

	cout << lo << '\n';
}

Compilation message (stderr)

joioi.cpp: In function 'int main()':
joioi.cpp:46:6: warning: unused variable 'res' [-Wunused-variable]
   46 |  int res = 2'000'000'001;
      |      ^~~

• Subtask 1: 15 / 15
• Subtask 2: 45 / 45
• Subtask 3: 40 / 40