Buggy python submission (verdict: Runtime Error):
n,k = map(int, input().split(" "))
s = list(input())

if s[0] == "0":
    s_num = [0]
else:
    s_num = []
pre = s[0]
num = 0

for i in s:
    if pre == i:
        num += 1
    else:
        s_num.append(num)
        num = 1
        pre = "1" if pre == "0" else "0"
else:
    s_num.append(num)

sums = [s_num[0]]

for i,e in enumerate(s_num[1:]):
    sums.append(sums[i] + e)

ret = 0
sums_len = len(sums)-1
for i in range(len(s_num)//2+1,2):
    ret = max(ret,(sums[min(i+k*2+1,sums_len)] - sums[i]))
 
print(ret)

Fixed submission:
n,k = map(int, input().split(" "))
s = list(input())

if s[0] == "0":
    s_num = [0]
else:
    s_num = []
pre = s[0]
num = 0

for i in s:
    if pre == i:
        num += 1
    else:
        s_num.append(num)
        num = 1
        pre = "1" if pre == "0" else "0"
else:
    s_num.append(num)

sums = [0]

for i,e in enumerate(s_num):
    sums.append(sums[i] + e)

ret = 0
sums_len = len(sums)-1
for i in range(0,len(sums),2):
    ret = max(ret,(sums[min(i+k*2+1,sums_len)] - sums[i]))
 
print(ret)

Buggy python submission (verdict: Runtime Error):
n,k = map(int, input().split(" "))
s = list(input())

s_num = []
s_first = s[0]
pre = s[0]
num = 0

for i in s:
    if pre == i:
        num += 1
    else:
        s_num.append(num)
        num = 1
        pre = "1" if pre == "0" else "0"
else:
    s_num.append(num)
ret = 0
if s_first == "0":
    ret = max(ret,sum(s_num[0:(2*k)]))
    for i in range(1,len(s_num)//2):
        ret = max(ret,sum(s_num[((i-1)*2+1):(2*(i+k))]))
else:
    ret = max(sum(s_num[0:(2*k+1)]))
    for i in range(1,len(s_num)//2):
        ret = max(ret,(sum(s_num[(i*2):(2*(k+i)+1)])))
 
print(ret)

Fixed submission:
n,k = map(int, input().split(" "))
s = list(input())

if s[0] == "0":
    s_num = [0]
else:
    s_num = []
pre = s[0]
num = 0

for i in s:
    if pre == i:
        num += 1
    else:
        s_num.append(num)
        num = 1
        pre = "1" if pre == "0" else "0"
else:
    s_num.append(num)

sums = [0]

for i,e in enumerate(s_num):
    sums.append(sums[i] + e)

ret = 0
sums_len = len(sums)-1
for i in range(0,len(sums),2):
    ret = max(ret,(sums[min(i+k*2+1,sums_len)] - sums[i]))
 
print(ret)

Buggy python submission (verdict: Runtime Error):
n,k = map(int, input().split(" "))
s = list(input())

s_num = []
s_first = s[0]
pre = s[0]
num = 0

for i in s:
    if pre == i:
        num += 1
    else:
        s_num.append(num)
        num = 1
        pre = "1" if pre == "0" else "0"
else:
    s_num.append(num)
ret = 0
if s_first == "0":
    ret.append(sum(s_num[0:(2*k)]))
    for i in range(1,len(s_num)//2):
        ret = max(ret,sum(s_num[((i-1)*2+1):(2*(i+k))]))
else:
    ret.append(sum(s_num[0:(2*k+1)]))
    for i in range(1,len(s_num)//2):
        ret = max(ret,(sum(s_num[(i*2):(2*(k+i)+1)])))
 
print(ret)

Fixed submission:
n,k = map(int, input().split(" "))
s = list(input())

if s[0] == "0":
    s_num = [0]
else:
    s_num = []
pre = s[0]
num = 0

for i in s:
    if pre == i:
        num += 1
    else:
        s_num.append(num)
        num = 1
        pre = "1" if pre == "0" else "0"
else:
    s_num.append(num)

sums = [0]

for i,e in enumerate(s_num):
    sums.append(sums[i] + e)

ret = 0
sums_len = len(sums)-1
for i in range(0,len(sums),2):
    ret = max(ret,(sums[min(i+k*2+1,sums_len)] - sums[i]))
 
print(ret)