Submission #444907

#	Time	Username	Problem	Language	Result	Execution time	Memory
444907		aryan12	The Kingdom of JOIOI (JOI17_joioi)	C++17	100 / 100	2152 ms	70712 KiB

joioi

#include <bits/stdc++.h>
using namespace std;
#define int long long

mt19937_64 RNG(chrono::steady_clock::now().time_since_epoch().count());

const int N = 2005;
int n, m;
vector<vector<int> > a(N, vector<int> (N));
int maxVal = 0, minVal = INT_MAX;

void FlipRows() {
	for(int i = 1; i <= n / 2; i++) {
		for(int j = 1; j <= m; j++) {
			swap(a[i][j], a[n - i + 1][j]);
		}
	}
}

void FlipColumns() {
	for(int i = 1; i <= n; i++) {
		for(int j = 1; j <= m / 2; j++) {
			swap(a[i][j], a[i][m - j + 1]);
		}
	}
}

bool Check(int max_delta) {
	int max_row = n;
	//cout << "max_delta = " << max_delta << "\n";
	for(int j = 1; j <= m; j++) {
		for(int i = 1; i <= max_row; i++) {
			if(maxVal - a[i][j] > max_delta) {
				max_row = i - 1;
				//cout << "In column " << j << ", the row max is being reduced to: " << i - 1 << "\n";
				break;
			}
		}
		for(int i = max_row + 1; i <= n; i++) {
			if(a[i][j] - minVal > max_delta) {
				//cout << "a[i][j] - minVal = " << a[i][j] - minVal << ", max_delta = " << max_delta << "\n";
				//cout << "a[i][j] = " << a[i][j] << ", minVal = " << minVal << "\n";
				//cout << "Exceeding the limits...can't take anymore\n";
				//cout << "Place = (" << i << ", " << j << ")\n";
				return false;
			}
		}
	}
	return true;
}

int FindVal() {
	int l = 0, r = maxVal - minVal + 1;
	int mid, ans = r;
	while(l <= r) {
		mid = (l + r) >> 1;
		if(Check(mid)) {
			ans = mid;
			r = mid - 1;
		}
		else {
			l = mid + 1;
		}
	}
	//cout << "ans = " << ans << "\n";
	return ans;
}

void Solve() {
	cin >> n >> m;
	for(int i = 1; i <= n; i++) {
		for(int j = 1; j <= m; j++) {
			cin >> a[i][j];
			maxVal = max(maxVal, a[i][j]);
			minVal = min(minVal, a[i][j]);
		}
	}

	/*cout << "maxVal = " << maxVal << ", minVal = " << minVal << "\n";
	for(int i = 1; i <= n; i++) {
		for(int j = 1; j <= m; j++) {
			cout << a[i][j] << " ";
		}
		cout << "\n";
	}*/

	int ans = FindVal();
	FlipColumns();

	/*for(int i = 1; i <= n; i++) {
		for(int j = 1; j <= m; j++) {
			cout << a[i][j] << " ";
		}
		cout << "\n";
	}*/


	ans = min(ans, FindVal());
	FlipRows();

	/*for(int i = 1; i <= n; i++) {
		for(int j = 1; j <= m; j++) {
			cout << a[i][j] << " ";
		}
		cout << "\n";
	}*/


	ans = min(ans, FindVal());
	FlipColumns();

	/*for(int i = 1; i <= n; i++) {
		for(int j = 1; j <= m; j++) {
			cout << a[i][j] << " ";
		}
		cout << "\n";
	}*/


	cout << min(ans, FindVal()) << "\n";
}

int32_t main() {
	auto begin = std::chrono::high_resolution_clock::now();
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	int t = 1;
	//cin >> t;
	while(t--) {
		Solve();
	}
	auto end = std::chrono::high_resolution_clock::now();
    auto elapsed = std::chrono::duration_cast<std::chrono::nanoseconds>(end - begin);
    cerr << "Time measured: " << elapsed.count() * 1e-9 << " seconds.\n"; 
	return 0;
}

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