B=enumerate
O=(0,1),(0,-1),(1,0),(-1,0)
C=lambda b:[(x,r,y,v)for x,r in B(b)for y,v in B(r)]
H=list.count
def I(b,x,y,s):
 b=eval(str(b));b[x][y]=0
 if b in s:return
 t=[(x,y)for x,_,y,v in C(b)if v];q=[t.pop()]
 while q:
  x,y=q.pop(0)
  for T,H in O:
   if(E:=(x+T,y+H))in t:q+=E,;t.remove(E)
 if[]==t:return b
def f(b):
 q,*s=[b],
 while q:
  b,R=q.pop(0),1
  for x,r,y,v in C(b):
   if v and(H(r,v)>1or H([*[*zip(*b)][y]],v)>1)and(R:=0)<all(b[x+T][y+H]for T,H in O if len(b)>x+T>-1<y+H<len(r))and(K:=I(b,x,y,s)):q+=K,;s+=K,
  if R:return b
 
s1 = '''
2 2 2 4
1 4 2 3
2 3 2 1
3 4 1 2
'''
s2 = '''
4 2 4 3
4 1 1 2
3 1 2 1
4 3 1 3
'''
s3 = '''
1 5 3 1 2
5 4 1 3 4
3 4 3 1 5
4 4 2 3 3
2 1 5 4 4
'''
def to_board(o_b):
	return [[*map(int, i.split())]for i in filter(None, o_b.split('\n'))]
 
print(f(to_board(s1)))
print(f(to_board(s2)))
print(f(to_board(s3)))

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