제출 #1299354

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
1299354		asdef	Bomb (IZhO17_bomb)	C++20	83 / 100	1101 ms	100328 KiB

bomb

#include<bits/stdc++.h>

using namespace std;

const int N = 2550;

int ans;
int x[N];
int n, m, a[N][N];
int s[N][N], H, W;
int f[N][N], bad[N][N];
int dpw[N], dph[N];
char S[N];

inline void press(int i, int j, int h, int w)
{
	bad[i][j]++;
	bad[i + h][j + w]++;
	bad[i + h][j]--;
	bad[i][j + w]--;
}

inline bool can(int h, int w)
{
	for(int i = 1; i <= n; ++i)
		for(int j = 1; j <= m; ++j)
			bad[i][j] = 0, f[i][j] = 0;
	for(int i = 1; i + h - 1 <= n; ++i)
		for(int j = 1; j + w - 1 <= m; ++j)
			if(s[i + h - 1][j + w - 1] - s[i + h - 1][j - 1] - s[i - 1][j + w - 1] + s[i - 1][j - 1] == h * w)
				press(i, j, h, w);
	for(int i = 1; i <= n; ++i)
		for(int j = 1; j <= m; ++j)
		{
			f[i][j] = f[i - 1][j] + f[i][j - 1] - f[i - 1][j - 1] + bad[i][j];
			if(a[i][j] == 1 && f[i][j] <= 0) 
				return false;
		}
	return true;
}

inline int getw(int h)
{
	if(dpw[h] != -1) return dpw[h];
	int L = 0, R = W + 1;
	while(L + 1 < R)
	{
		int w = (L + R) >> 1;
		if(can(h, w))
			L = w;
		else
			R = w;
	}
	return dpw[h] = L;
}

inline int geth(int w)
{
	if(dph[w] != -1) return dph[w];
	int L = 0, R = H + 1;
	while(L + 1 < R)
	{
		int h = (L + R) >> 1;
		if(can(h, w))
			L = h;
		else
			R = h;
	}
	return dph[w] = L;
}

int main()
{
	// freopen("bomb.in", "r", stdin);
	// freopen("bomb.out", "w", stdout);

	scanf("%d%d", &n, &m);

	for(int i = 0; i < 2550; ++i)
		dpw[i] = dph[i] = -1;
	for(int i = 2; i <= n + 1; ++i)
	{
		scanf("%s\n", S);
		for(int j = 2; j <= m + 1; ++j)
			a[i][j] = S[j - 2] - '0';
	}
	
	n += 2, m += 2;

	for(int i = 1; i <= n; ++i)
		for(int j = 1; j <= m; ++j)
			s[i][j] = s[i - 1][j] + s[i][j - 1] - s[i - 1][j - 1] + a[i][j];
	
	H = n, W = m;

	for(int i = 1; i <= n; ++i)
	{
		int cnt = 0;
		for(int j = 1; j <= m; ++j)
			if(a[i][j] == 1) cnt++;
			else 
			{
				if(cnt) W = min(W, cnt);
				cnt = 0;
			}
	}

	for(int j = 1; j <= m; ++j)
	{
		int cnt = 0;
		for(int i = 1; i <= n; ++i)
			if(a[i][j] == 1) cnt++;
			else
			{
				if(cnt) H = min(H, cnt);
				cnt = 0;
			}
	}

	for(int i = 1; i <= H;)
	{
		int x = getw(i);
		int y = geth(x);
		ans = max(ans, y * x);
		i = y + 1;
	}

	ans = max(ans, max(W, H));
	printf("%d\n", ans);
		
	return 0;
}

컴파일 시 표준 에러 (stderr) 메시지

bomb.cpp: In function 'int main()':
bomb.cpp:77:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   77 |         scanf("%d%d", &n, &m);
      |         ~~~~~^~~~~~~~~~~~~~~~
bomb.cpp:83:22: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   83 |                 scanf("%s\n", S);
      |                 ~~~~~^~~~~~~~~~~

• Subtask 1: 83 / 100