Submission #705299

#	Time	Username	Problem	Language	Result	Execution time	Memory
705299		rainboy	The Kingdom of JOIOI (JOI17_joioi)	C11	0 / 100	1 ms	340 KiB

joioi

#include <stdio.h>

#define N	2000
#define M	2000
#define INF	0x3f3f3f3f

int min(int a, int b) { return a < b ? a : b; }
int max(int a, int b) { return a > b ? a : b; }

int aa[N][M], aa_[N][M], n, m, d;

int solve_(int d) {
	static char good[N][M * 2];
	int i, j, k, s, t, mn, mx;

	mn = INF, mx = -1;
	for (i = 0; i < n; i++)
		for (j = 0; j < m; j++)
			mn = min(mn, aa[i][j]), mx = max(mx, aa[i][j]);
	for (i = 0; i < n; i++) {
		k = 0;
		for (j = 0; j < m; j++)
			if (mx - aa[i][j] > d)
				k++;
		for (j = 0; j < m; j++) {
			good[i][j] = k == 0;
			if (mx - aa[i][j] > d)
				k--;
			if (aa[i][j] - mn > d)
				k++;
		}
		for (j = 0; j < m; j++) {
			good[i][m + j] = k == 0;
			if (aa[i][j] - mn > d)
				k++;
			if (mx - aa[i][j] > d)
				k--;
		}
	}
	for (s = 0; s < m * 2; s++) {
		t = s + m * 2;
		for (i = 0, j = s; i < n && j < s + m * 2; i++)
			while (j < s + m * 2 && !good[i][j % (m * 2)])
				j++;
		if (j < t)
			return 1;
	}
	return 0;
}

int solve(int d) {
	int h, i, j, jl, jr, tmp;

	for (i = 0; i < n; i++)
		for (j = 0; j < m; j++)
			aa_[i][j] = aa[i][j];
	for (h = 0; h < 2; h++) {
		if (solve_(d))
			return 1;
		for (i = 0; i < n; i++)
			for (jl = 0, jr = m - 1; jl < jr; jl++, jr--)
				tmp = aa_[i][jl], aa_[i][jl] = aa_[i][jr], aa_[i][jr] = tmp;
	}
	return 0;
}

int main() {
	int i, j, lower, upper;

	scanf("%d%d", &n, &m);
	for (i = 0; i < n; i++)
		for (j = 0; j < m; j++)
			scanf("%d", &aa[i][j]);
	lower = -1, upper = INF;
	while (upper - lower > 1) {
		int d = (lower + upper) / 2;

		if (solve(d))
			upper = d;
		else
			lower = d;
	}
	printf("%d\n", upper);
	return 0;
}

Compilation message (stderr)

joioi.c: In function 'main':
joioi.c:70:2: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   70 |  scanf("%d%d", &n, &m);
      |  ^~~~~~~~~~~~~~~~~~~~~
joioi.c:73:4: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   73 |    scanf("%d", &aa[i][j]);
      |    ^~~~~~~~~~~~~~~~~~~~~~

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