Submission #88109

#	Time	Username	Problem	Language	Result	Execution time	Memory
88109		Pajaraja	Bomb (IZhO17_bomb)	C++17	43 / 100	1096 ms	69340 KiB

bomb

#include <bits/stdc++.h>
#define MAXN 2507
using namespace std;
bool t[MAXN][MAXN],r[MAXN][MAXN];
int p[MAXN][MAXN],d[MAXN][MAXN],n,m;
char s[MAXN][MAXN];
bool provera(int x,int y)
{
	for(int i=x;i<=n;i++) for(int j=y;j<=m;j++) r[i][j]=(p[i][j]-p[i-x][j]-p[i][j-y]+p[i-x][j-y]==x*y);
	for(int i=n;i>0;i--) for(int j=m;j>0;j--) d[i][j]=r[i][j]+d[i+1][j]+d[i][j+1]-d[i+1][j+1];
	for(int i=1;i<=n;i++) for(int j=1;j<=m;j++) if(t[i][j] && d[i][j]-d[min(n+1,i+x)][j]-d[i][min(m+1,j+y)]+d[min(n+1,i+x)][min(m+1,j+y)]==0) return false;
	return true;
}
int main()
{
	int lh=2507,lv=2507;
	scanf("%d%d",&n,&m);
	for(int i=1;i<=n;i++)
	{
		scanf("%s",s[i]);
		for(int j=1;j<=m;j++) t[i][j]=(s[i][j-1]=='1'?1:0);
	}
	for(int i=1;i<=n;i++)
	{
		int cur=0;
		for(int j=1;j<=m;j++)
		{
			if(t[i][j]==0) {if(cur!=0) lh=min(lh,cur); cur=0;}
			else cur++;
		}
		if(cur!=0) lh=min(lh,cur);
	}
	for(int i=1;i<=m;i++)
	{
		int cur=0;
		for(int j=1;j<=n;j++)
		{
			if(t[j][i]==0) {if(cur!=0) lv=min(lv,cur); cur=0;}
			else cur++;
		}
		if(cur!=0) lv=min(lv,cur);
	}
	int sol=0;
	for(int i=1;i<=n;i++) for(int j=1;j<=m;j++) p[i][j]=t[i][j]+p[i-1][j]+p[i][j-1]-p[i-1][j-1];
	for(int i=1;i<=lv;i++)
	{
		while(!provera(i,lh)) lh--; 
		if(sol>lh*n) break;
		sol=max(sol,lh*i);
	}
	printf("%d",sol);
}

Compilation message (stderr)

bomb.cpp: In function 'int main()':
bomb.cpp:17:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d",&n,&m);
  ~~~~~^~~~~~~~~~~~~~
bomb.cpp:20:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%s",s[i]);
   ~~~~~^~~~~~~~~~~

• Subtask 1: 43 / 100