Submission #37228

# Submission time Handle Problem Language Result Execution time Memory
37228 2017-12-22T17:52:14 Z alenam0161 Bomb (IZhO17_bomb) C++14
46 / 100
1000 ms 103648 KB
#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;
}

Compilation message

bomb.cpp: In function 'int main()':
bomb.cpp:77:23: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d", &n, &m);
                       ^
bomb.cpp:83:19: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%s\n", S);
                   ^
# Verdict Execution time Memory Grader output
1 Correct 0 ms 103648 KB Output is correct
2 Correct 0 ms 103648 KB Output is correct
3 Correct 6 ms 103648 KB Output is correct
4 Correct 6 ms 103648 KB Output is correct
5 Correct 0 ms 103648 KB Output is correct
6 Correct 0 ms 103648 KB Output is correct
7 Correct 0 ms 103648 KB Output is correct
8 Correct 0 ms 103648 KB Output is correct
9 Correct 0 ms 103648 KB Output is correct
10 Correct 0 ms 103648 KB Output is correct
11 Correct 0 ms 103648 KB Output is correct
12 Correct 0 ms 103648 KB Output is correct
13 Correct 0 ms 103648 KB Output is correct
14 Correct 0 ms 103648 KB Output is correct
15 Correct 0 ms 103648 KB Output is correct
16 Correct 0 ms 103648 KB Output is correct
17 Correct 0 ms 103648 KB Output is correct
18 Correct 0 ms 103648 KB Output is correct
19 Correct 0 ms 103648 KB Output is correct
20 Correct 3 ms 103648 KB Output is correct
21 Correct 0 ms 103648 KB Output is correct
22 Correct 3 ms 103648 KB Output is correct
23 Correct 3 ms 103648 KB Output is correct
24 Correct 0 ms 103648 KB Output is correct
25 Correct 3 ms 103648 KB Output is correct
26 Correct 0 ms 103648 KB Output is correct
27 Correct 3 ms 103648 KB Output is correct
28 Correct 33 ms 103648 KB Output is correct
29 Correct 446 ms 103648 KB Output is correct
30 Correct 56 ms 103648 KB Output is correct
31 Correct 39 ms 103648 KB Output is correct
32 Correct 43 ms 103648 KB Output is correct
33 Correct 76 ms 103648 KB Output is correct
34 Correct 39 ms 103648 KB Output is correct
35 Correct 46 ms 103648 KB Output is correct
36 Correct 19 ms 103648 KB Output is correct
37 Correct 0 ms 103648 KB Output is correct
38 Execution timed out 1000 ms 103648 KB Execution timed out
39 Correct 0 ms 103648 KB Output is correct
40 Correct 363 ms 103648 KB Output is correct
41 Correct 0 ms 103648 KB Output is correct
42 Correct 19 ms 103648 KB Output is correct
43 Execution timed out 1000 ms 103648 KB Execution timed out
44 Execution timed out 1000 ms 103648 KB Execution timed out
45 Execution timed out 1000 ms 103648 KB Execution timed out
46 Correct 729 ms 103648 KB Output is correct
47 Execution timed out 1000 ms 103648 KB Execution timed out
48 Execution timed out 1000 ms 103648 KB Execution timed out
49 Correct 589 ms 103648 KB Output is correct
50 Execution timed out 1000 ms 103648 KB Execution timed out
51 Execution timed out 1000 ms 103648 KB Execution timed out
52 Execution timed out 1000 ms 103648 KB Execution timed out
53 Execution timed out 1000 ms 103648 KB Execution timed out
54 Execution timed out 1000 ms 103648 KB Execution timed out
55 Execution timed out 1000 ms 103648 KB Execution timed out
56 Execution timed out 1000 ms 103648 KB Execution timed out
57 Execution timed out 1000 ms 103648 KB Execution timed out
58 Execution timed out 1000 ms 103648 KB Execution timed out
59 Execution timed out 1000 ms 103648 KB Execution timed out
60 Correct 746 ms 103648 KB Output is correct
61 Correct 726 ms 103648 KB Output is correct
62 Execution timed out 1000 ms 103648 KB Execution timed out
63 Execution timed out 1000 ms 103648 KB Execution timed out
64 Correct 986 ms 103648 KB Output is correct
65 Execution timed out 1000 ms 103648 KB Execution timed out
66 Execution timed out 1000 ms 103648 KB Execution timed out
67 Execution timed out 1000 ms 103648 KB Execution timed out
68 Execution timed out 1000 ms 103648 KB Execution timed out
69 Execution timed out 1000 ms 103648 KB Execution timed out
70 Execution timed out 1000 ms 103648 KB Execution timed out
71 Execution timed out 1000 ms 103648 KB Execution timed out
72 Execution timed out 1000 ms 103648 KB Execution timed out
73 Execution timed out 1000 ms 103648 KB Execution timed out
74 Execution timed out 1000 ms 103648 KB Execution timed out
75 Execution timed out 1000 ms 103648 KB Execution timed out
76 Execution timed out 1000 ms 103648 KB Execution timed out
77 Execution timed out 1000 ms 103648 KB Execution timed out
78 Execution timed out 1000 ms 103648 KB Execution timed out
79 Execution timed out 1000 ms 103648 KB Execution timed out
80 Execution timed out 1000 ms 103648 KB Execution timed out
81 Execution timed out 1000 ms 103648 KB Execution timed out
82 Execution timed out 1000 ms 103648 KB Execution timed out
83 Execution timed out 1000 ms 103648 KB Execution timed out
84 Execution timed out 1000 ms 103648 KB Execution timed out
85 Execution timed out 1000 ms 103648 KB Execution timed out
86 Execution timed out 1000 ms 103648 KB Execution timed out
87 Execution timed out 1000 ms 103648 KB Execution timed out
88 Execution timed out 1000 ms 103648 KB Execution timed out
89 Execution timed out 1000 ms 103648 KB Execution timed out
90 Execution timed out 1000 ms 103648 KB Execution timed out
91 Execution timed out 1000 ms 103648 KB Execution timed out
92 Execution timed out 1000 ms 103648 KB Execution timed out
93 Execution timed out 1000 ms 103648 KB Execution timed out
94 Execution timed out 1000 ms 103648 KB Execution timed out
95 Execution timed out 1000 ms 103648 KB Execution timed out
96 Execution timed out 1000 ms 103648 KB Execution timed out
97 Execution timed out 1000 ms 103648 KB Execution timed out
98 Execution timed out 1000 ms 103648 KB Execution timed out
99 Execution timed out 1000 ms 103648 KB Execution timed out
100 Execution timed out 1000 ms 103648 KB Execution timed out