Submission #1033331

#	Time	Username	Problem	Language	Result	Execution time	Memory
1033331		vjudge1	The Kingdom of JOIOI (JOI17_joioi)	C++17	100 / 100	937 ms	51600 KiB

joioi

#include <bits/stdc++.h>
using namespace std;
 
const int N = 2005;
 
int n, m, mn = 1e9, a[N][N], b[N][N], f[N];
 
bool check0(int x) {
	f[0] = 1e9;
	int _mn, _mx;
	_mn = 1e9, _mx = 0;
	for (int i = 1; i <= n; ++i) {
		int mx = 0; f[i] = 0;
		for (int j = 1; j <= m; ++j) {
			mx = max(mx, b[i][j]);
			if (mx - mn > x) break;
			f[i]++;
		}
		f[i] = min(f[i], f[i - 1]);
		for (int j = f[i] + 1; j <= m; ++j) {
			_mn = min(_mn, b[i][j]);
			_mx = max(_mx, b[i][j]);
		}
	}
	return _mx - _mn <= x;
}
 
bool check1(int x) {
	bool ok = 0;
	for (int i = 1; i <= n; ++i) {
		for (int j = 1; j <= m; ++j) {
			b[i][j] = a[i][j];
		}
	}
	ok |= check0(x);
	for (int i = 1; i <= n; ++i) {
		for (int j = 1; j <= m; ++j) {
			b[i][j] = a[i][m - j + 1];
		}
	}
	ok |= check0(x);
	for (int i = 1; i <= n; ++i) {
		for (int j = 1; j <= m; ++j) {
			b[i][j] = a[n - i + 1][j];
		}
	}
	ok |= check0(x);
	for (int i = 1; i <= n; ++i) {
		for (int j = 1; j <= m; ++j) {
			b[i][j] = a[n - i + 1][m - j + 1];
		}
	}
	ok |= check0(x);
	return ok;
}
 
int main() {
	ios::sync_with_stdio(false);
	cin >> n >> m;
	for (int i = 1; i <= n; ++i) {
		for (int j = 1; j <= m; ++j) {
			cin >> a[i][j], mn = min(mn, a[i][j]);
		}
	}
 
	int l = 0, r = 1e9;
	while (l < r) {
		int mid = (l + r) >> 1;
		if (check1(mid)) r = mid;
		else l = mid + 1;
	}
	cout << l;
}

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