为何RE加WA

#include<bits/stdc++.h>
using namespace std;
int main()
{
	int r,c,s=0;
	char a[1005][1005];
	cin>>r>>c;
	for(int i=1;i<=r;i++)
		for(int j=1;j<=c;j++)
			cin>>a[i][j];
	for(int i=1;i<=r;i++)
	{
		for(int j=1;j<=c;j++)
		{
			if(a[i][j]=='#')
			{
				s++;
				a[i][j]='.';
				while(1)
				{
					int n,m;
					n+=i;m+=j;
					if(a[n][m+1]=='#')a[n][m+1]='.';m++;
					if(a[n][m-1]=='#')a[n][m-1]='.';m--;
					if(a[n+1][m]=='#')a[n+1][m]='.';n++;
					if(a[n-1][m]=='#')a[n-1][m]='.';n--;
					if(a[n][m+1]=='.' && a[n][m-1]=='.' && a[n-1][m]=='.' && a[n+1][m]=='.')a[n][m]='.';break;
				}
			}
		}
	}
	if(s!=0)
	{
		cout<<"There are "<<s<<" ships.";
		return 0;
	}
	cout<<"Bad placement.";
	return 0;
}