Buggy python submission (verdict: Runtime Error):
H,W = map(int,raw_input().split())
 
s = []
for i in range(H):
	s.append(raw_input())
 
flag=True
for i in range(H):
	for j in range(W):
		if s[i][j]=='#':
			local_flag=False
			if i+1<H:
				if s[i+1][j]=='#':
					local_flag=True
			if j+1<W:
				if s[i][j+1]=='#':
					local_flag=True
			if i-1>=0:
				if s[i-1][j]=='#':
					local_flag=True
			if j-1>=0:
				if s[i][j-1]=='#':
					local_flag=True
			if local_flag=False:
				flag=False
if flag:
	print 'Yes'
else:
	print 'No'

Fixed submission:
H,W = map(int,raw_input().split())
 
s = []
for i in range(H):
	s.append(raw_input())
 
flag=True
for i in range(H):
	for j in range(W):
		if s[i][j]=='#':
			local_flag=False
			if i+1<H:
				if s[i+1][j]=='#':
					local_flag=True
			if j+1<W:
				if s[i][j+1]=='#':
					local_flag=True
			if i-1>=0:
				if s[i-1][j]=='#':
					local_flag=True
			if j-1>=0:
				if s[i][j-1]=='#':
					local_flag=True
			if local_flag==False:
				flag=False
if flag:
	print 'Yes'
else:
	print 'No'

Buggy python submission (verdict: Runtime Error):

H,W = map(int,raw_input().split())
 
s = []
for i in range(H):
	s.append(raw_input())
 
flag=True
for i in range(H):
	for j in range(W):
 
		if s[i][j]=='#':
			local_flag=False
			if i+1<H:
			  if s[i+1][j]=='#':
					local_flag=True
			if j+1<W:
			  if s[i][j+1]=='#':
					local_flag=True
			if i-1>=0:
			  if s[i-1][j]=='#':
					local_flag=True
			if j-1>=0:
				if s[i][j-1]=='#':
					local_flag=True
			if local_flag=False:
				flag=False
if flag:
	print 'Yes'
else:
	print 'No'

Fixed submission:
H,W = map(int,raw_input().split())
 
s = []
for i in range(H):
	s.append(raw_input())
 
flag=True
for i in range(H):
	for j in range(W):
		if s[i][j]=='#':
			local_flag=False
			if i+1<H:
				if s[i+1][j]=='#':
					local_flag=True
			if j+1<W:
				if s[i][j+1]=='#':
					local_flag=True
			if i-1>=0:
				if s[i-1][j]=='#':
					local_flag=True
			if j-1>=0:
				if s[i][j-1]=='#':
					local_flag=True
			if local_flag==False:
				flag=False
if flag:
	print 'Yes'
else:
	print 'No'

Buggy python submission (verdict: Runtime Error):
H,W = map(int,raw_input().split())

s = []
for i in range(H):
  s.append(raw_input())

flag=True
for i in range(H):
  for j in range(W):

    if s[i][j]=='#':
    	local_flag=False
		if i+1<H:
          if s[i+1][j]=='#':
            local_flag=True
        if j+1<W:
          if s[i][j+1]=='#':
            local_flag=True
        if i-1>=0:
          if s[i-1][j]=='#':
            local_flag=True
        if j-1>=0:
          if s[i][j-1]=='#':
            local_flag=True
        if local_flag=False:
          flag=False
if flag:
  print 'Yes'
else:
  print 'No'

Fixed submission:
H,W = map(int,raw_input().split())
 
s = []
for i in range(H):
	s.append(raw_input())
 
flag=True
for i in range(H):
	for j in range(W):
		if s[i][j]=='#':
			local_flag=False
			if i+1<H:
				if s[i+1][j]=='#':
					local_flag=True
			if j+1<W:
				if s[i][j+1]=='#':
					local_flag=True
			if i-1>=0:
				if s[i-1][j]=='#':
					local_flag=True
			if j-1>=0:
				if s[i][j-1]=='#':
					local_flag=True
			if local_flag==False:
				flag=False
if flag:
	print 'Yes'
else:
	print 'No'