```
class solution:
def solve(self, A, B):
i, n, bulb = 0, len(A), 0
while i < n:
flag = False
j = min(i+B-1, n-1)
while j>=i-B+1 and j<n and j>0:
flag = True
bulb += 1
i = j + B
break
j -= 1
if not flag:
return -1
return bulb
```

# Simple iteration in Python

it means, it will keep in boundation of length of an array. **(i+B-1)** is the maximum distance of glow light, if sometimes i+B-1 gives greater value than length of array then it will min() function takes n-1 value instead of i+B-1.

suppose for an example, n=8, B=3 and at iteration value i=4

value of i+B-1 = 4+3-1 = 6 here 6<(n-1) so j will take 6. but when iteration value iterate at i=6 then,

i+B-1 = 6+3-1 = 8 where 8>(n-1) this is out of size of an array then j will takes 7 instead of 8 because it means light glow distance is at last index of array.

j = min(i+B-1, n-1)

this function is use for maintaining the length boundation of an array.

```
def solve(self, A, B):
i, n, bulb = 0, len(A), 0
while i < n:
flag = False
j = min(i+B-1, n-1)
while j>=i-B+1 and j<n and j>0:
if A[j] ==1:
flag = True
bulb += 1
i = j + B
break
j -= 1
if not flag:
return -1
return bulb
```

Your code does not checks the condition of whether the bulb is working(i.e 1 ) or not. and also decrementing the j should be inside the while loop`Preformatted text`

please recheck once again the code. it accepting all the conditions which fulfil the question. `j`

is already inside the while loop. or if you have any strong TC then please share that one which fail the case of this code.

This is the code that I modified and shared I am talking about your code, where if A[j] == 1: the condition is missing