Submission #684201

#	Time	Username	Problem	Language	Result	Execution time	Memory
684201		ethening	The Kingdom of JOIOI (JOI17_joioi)	C++17	60 / 100	4102 ms	196024 KiB

joioi

#include "bits/stdc++.h"
#include <climits>
using namespace std;
using ll = long long;

int h, w;
int a[2005][2005];
int minv, maxv;

int t[2005][2005];

int t1[3][2005][2005];
int t2[3][2005][2005];
int t3[3][2005][2005];
int t4[3][2005][2005];

bool check(int thr) {
	// cout << "!!" << thr << endl;
	for (int i = 1; i <= h; i++) {
		for (int j = 1; j <= w; j++) {
			t[i][j] = 0;
			if (a[i][j] <= minv + thr) {
				t[i][j] += 1;
			}
			if (a[i][j] >= maxv - thr) {
				t[i][j] += 2;
			}
			// cout << i << " " << j << " " << t[i][j] << endl;
			if (t[i][j] == 0) return false;
		}
	}
	for (int k = 1; k <= 2; k++) {
		for (int i = 1; i <= h; i++) {
			for (int j = 1; j <= w; j++) {
				t1[k][i][j] = (t[i][j] == k);
				t1[k][i][j] = max(t1[k][i][j], max(t1[k][i - 1][j], t1[k][i][j - 1]));
			}
		}
		for (int i = 1; i <= h; i++) {
			for (int j = w; j >= 1; j--) {
				t2[k][i][j] = (t[i][j] == k);
				t2[k][i][j] = max(t2[k][i][j], max(t2[k][i - 1][j], t2[k][i][j + 1]));
			}
		}
		for (int i = h; i >= 1; i--) {
			for (int j = 1; j <= w; j++) {
				t3[k][i][j] = (t[i][j] == k);
				t3[k][i][j] = max(t3[k][i][j], max(t3[k][i + 1][j], t3[k][i][j - 1]));
			}
		}
		for (int i = h; i >= 1; i--) {
			for (int j = w; j >= 1; j--) {
				t4[k][i][j] = (t[i][j] == k);
				t4[k][i][j] = max(t4[k][i][j], max(t4[k][i + 1][j], t4[k][i][j + 1]));
			}
		}
	}

	// 1 2
	// 3 4

	bool flag1 = 1, flag2 = 1, flag3 = 1, flag4 = 1;
	for (int i = 1; i <= h; i++) {
		for (int j = 1; j <= w; j++) {
			if (t1[1][i][j] == 1 && t4[2][i][j] == 1) flag1 = 0;
			if (t2[1][i][j] == 1 && t3[2][i][j] == 1) flag2 = 0;
			if (t3[1][i][j] == 1 && t2[2][i][j] == 1) flag3 = 0;
			if (t4[1][i][j] == 1 && t1[2][i][j] == 1) flag4 = 0;
		}
	}
	return flag1 || flag2 || flag3 || flag4;
}


int main() {
	cin.tie(0)->sync_with_stdio(0);
	
	cin >> h >> w;
	minv = INT_MAX;
	maxv = INT_MIN;
	for (int i = 1; i <= h; i++) {
		for (int j = 1; j <= w; j++) {
			cin >> a[i][j];
			minv = min(minv, a[i][j]);
			maxv = max(maxv, a[i][j]);
		}
	}

	if (minv == maxv) {
		cout << 0 << endl;
		return 0;
	}
	int l = 0, r = maxv - minv;
	while (l <= r) {
		int d = (l + r) / 2;
		if (check(d)) {
			r = d - 1;
		}
		else {
			l = d + 1;
		}
	}
	cout << l << endl;
}

• Subtask 1: 15 / 15
• Subtask 2: 45 / 45
• Subtask 3: 0 / 40