Submission #684210

#	Time	Username	Problem	Language	Result	Execution time	Memory
684210		ethening	The Kingdom of JOIOI (JOI17_joioi)	C++17	100 / 100	2443 ms	117728 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 t2[2005][2005];
int t3[2005][2005];
int t4[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;
			t2[w - j + 1][i] = t[i][j];
			t3[h - i + 1][w - j + 1] = t[i][j];
			t4[j][h - i + 1] = t[i][j];
		}
	}
	
	bool flag1 = 1, flag2 = 1, flag3 = 1, flag4 = 1;
	{
		int small_right_most = 0;
		int big_left_most = w + 1;
		for (int i = 1; i <= h && flag1 == 1; i++) {
			int cur_small_right_most = 0;
			int cur_big_left_most = w + 1;
			for (int j = 1; j <= w; j++) {
				if (t[i][j] == 1) {
					cur_small_right_most = max(cur_small_right_most, j);
				}
				if (t[i][j] == 2) {
					cur_big_left_most = min(cur_big_left_most, j);
				}
			}
			if (cur_small_right_most >= cur_big_left_most) {
				flag1 = 0;
				break;
			}
			if (small_right_most >= cur_big_left_most) {
				flag1 = 0;
				break;
			}
			small_right_most = max(small_right_most, cur_small_right_most);
			big_left_most = cur_big_left_most;
		}
	}
	{
		int small_right_most = 0;
		int big_left_most = w + 1;
		for (int i = 1; i <= h && flag3 == 1; i++) {
			int cur_small_right_most = 0;
			int cur_big_left_most = w + 1;
			for (int j = 1; j <= w; j++) {
				if (t3[i][j] == 1) {
					cur_small_right_most = max(cur_small_right_most, j);
				}
				if (t3[i][j] == 2) {
					cur_big_left_most = min(cur_big_left_most, j);
				}
			}
			if (cur_small_right_most >= cur_big_left_most) {
				flag3 = 0;
				break;
			}
			if (small_right_most >= cur_big_left_most) {
				flag3 = 0;
				break;
			}
			small_right_most = max(small_right_most, cur_small_right_most);
			big_left_most = cur_big_left_most;
		}
	}
	{
		int small_right_most = 0;
		int big_left_most = h + 1;
		for (int i = 1; i <= w && flag2 == 1; i++) {
			int cur_small_right_most = 0;
			int cur_big_left_most = h + 1;
			for (int j = 1; j <= h; j++) {
				if (t2[i][j] == 1) {
					cur_small_right_most = max(cur_small_right_most, j);
				}
				if (t2[i][j] == 2) {
					cur_big_left_most = min(cur_big_left_most, j);
				}
			}
			if (cur_small_right_most >= cur_big_left_most) {
				flag2 = 0;
				break;
			}
			if (small_right_most >= cur_big_left_most) {
				flag2 = 0;
				break;
			}
			small_right_most = max(small_right_most, cur_small_right_most);
			big_left_most = cur_big_left_most;
		}
	}
	{
		int small_right_most = 0;
		int big_left_most = h + 1;
		for (int i = 1; i <= w && flag4 == 1; i++) {
			int cur_small_right_most = 0;
			int cur_big_left_most = h + 1;
			for (int j = 1; j <= h; j++) {
				if (t4[i][j] == 1) {
					cur_small_right_most = max(cur_small_right_most, j);
				}
				if (t4[i][j] == 2) {
					cur_big_left_most = min(cur_big_left_most, j);
				}
			}
			if (cur_small_right_most >= cur_big_left_most) {
				flag4 = 0;
				break;
			}
			if (small_right_most >= cur_big_left_most) {
				flag4 = 0;
				break;
			}
			small_right_most = max(small_right_most, cur_small_right_most);
			big_left_most = cur_big_left_most;
		}
	}
	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;
}

Compilation message (stderr)

joioi.cpp: In function 'bool check(int)':
joioi.cpp:42:7: warning: variable 'big_left_most' set but not used [-Wunused-but-set-variable]
   42 |   int big_left_most = w + 1;
      |       ^~~~~~~~~~~~~
joioi.cpp:68:7: warning: variable 'big_left_most' set but not used [-Wunused-but-set-variable]
   68 |   int big_left_most = w + 1;
      |       ^~~~~~~~~~~~~
joioi.cpp:94:7: warning: variable 'big_left_most' set but not used [-Wunused-but-set-variable]
   94 |   int big_left_most = h + 1;
      |       ^~~~~~~~~~~~~
joioi.cpp:120:7: warning: variable 'big_left_most' set but not used [-Wunused-but-set-variable]
  120 |   int big_left_most = h + 1;
      |       ^~~~~~~~~~~~~

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