Buggy python submission (verdict: Runtime Error):
n,k = map(int, input().split())
s = input()
cnt = 0
init = (s[0]=='1')
h=[1]
h_cnt = 0

for i in range(1,n):
    if(s[i]!=s[i-1]):
        h_cnt+=1
        h.append(1)
    else:
        h[h_cnt]+=1

h_cnt+=1

zero_num = 0
ans = 0

if(init): #start with 1
    zero_num = h_cnt//2;
    if(zero_num<=k):
        ans = n
    else:
        sum_0 = sum(h[0:k*2+1])
        ans = sum_0
        h = h +[0]
        for j in range(0,zero_num-k): #j is 0's order
            sum_0 = sum_0 - h[j*2] - h[j*2+1] + h[(j+k)*2+1] + h[(j+k)*2+2]
            if(ans<=sum_0):
                ans = sum_0

else: #start with 0
    zero_num = h_cnt//2 +1;
    if(zero_num<=k):
        ans = n
    else:
        sum_0 = sum(h[0:k*2])
        ans = sum_0
        h = [0] + h +[0]
        for j in range(0,zero_num-k): #j is 0's order
            sum_0 = sum_0 - h[j*2] - h[j*2+1] + h[(j+k)*2+1] + h[(j+k)*2+2]
            if(ans<=sum_0):
                ans = sum_0

print(ans)

Fixed submission:
n,k = map(int, input().split())
s = input()
cnt = 0
init = (s[0]=='1')
h=[1]
h_cnt = 0

for i in range(1,n):
    if(s[i]!=s[i-1]):
        h_cnt+=1
        h.append(1)
    else:
        h[h_cnt]+=1

h_cnt+=1

zero_num = 0
ans = 0

if(init): #start with 1
    zero_num = h_cnt//2;
    if(zero_num<=k):
        ans = n
    else:
        sum_0 = sum(h[0:k*2+1])
        ans = sum_0
        h = h +[0,0,0]
        for j in range(0,zero_num-k): #j is 0's order
            sum_0 = sum_0 - h[j*2] - h[j*2+1] + h[(j+k)*2+1] + h[(j+k)*2+2]
            if(ans<=sum_0):
                ans = sum_0

else: #start with 0
    zero_num = h_cnt//2 +1;
    if(zero_num<=k):
        ans = n
    else:
        sum_0 = sum(h[0:k*2])
        ans = sum_0
        h = [0] + h +[0,0,0]
        for j in range(0,zero_num-k):#j is 0's order
            sum_0 = sum_0 - h[j*2] - h[j*2+1] + h[(j+k)*2+1] + h[(j+k)*2+2]
            if(ans<=sum_0):
                ans = sum_0

print(ans)

Buggy python submission (verdict: Runtime Error):
n,k = map(int, input().split())
s = input()
cnt = 0
init = (s[0]=='1')
h=[1]
h_cnt = 0

for i in range(1,n):
    if(s[i]!=s[i-1]):
        h_cnt+=1
        h.append(1)
    else:
        h[h_cnt]+=1

h_cnt+=1

zero_num = 0
ans = 0

if(init): #start with 1
    zero_num = h_cnt//2;
    if(zero_num<=k):
        ans = n
    else:
        sum_0 = sum(h[0:k*2+1])
        ans = sum_0
        h = h +[0]
        for j in range(0,zero_num-k): #j is 0's order
            sum_0 = sum_0 - h[j*2] - h[j*2+1] + h[(j+k)*2+1] + h[(j+k)*2+2]
            if(ans<=sum_0):
                ans = sum_0

else: #start with 0
    zero_num = h_cnt//2 +1;
    if(zero_num<=k):
        ans = n
    else:
        sum_0 = sum(h[0:k*2])
        ans = sum_0
        h = [0] + h +[0]
        for j in range(0,zero_num-k):#j is 0's order
            sum_0 = sum_0 - h[j*2] - h[j*2+1] + h[(j+k)*2+1] + h[(j+k)*2+2]
            if(ans<=sum_0):
                ans = sum_0

print(ans)

Fixed submission:
n,k = map(int, input().split())
s = input()
cnt = 0
init = (s[0]=='1')
h=[1]
h_cnt = 0

for i in range(1,n):
    if(s[i]!=s[i-1]):
        h_cnt+=1
        h.append(1)
    else:
        h[h_cnt]+=1

h_cnt+=1

zero_num = 0
ans = 0

if(init): #start with 1
    zero_num = h_cnt//2;
    if(zero_num<=k):
        ans = n
    else:
        sum_0 = sum(h[0:k*2+1])
        ans = sum_0
        h = h +[0,0,0]
        for j in range(0,zero_num-k): #j is 0's order
            sum_0 = sum_0 - h[j*2] - h[j*2+1] + h[(j+k)*2+1] + h[(j+k)*2+2]
            if(ans<=sum_0):
                ans = sum_0

else: #start with 0
    zero_num = h_cnt//2 +1;
    if(zero_num<=k):
        ans = n
    else:
        sum_0 = sum(h[0:k*2])
        ans = sum_0
        h = [0] + h +[0,0,0]
        for j in range(0,zero_num-k):#j is 0's order
            sum_0 = sum_0 - h[j*2] - h[j*2+1] + h[(j+k)*2+1] + h[(j+k)*2+2]
            if(ans<=sum_0):
                ans = sum_0

print(ans)

Buggy python submission (verdict: Runtime Error):
[n,k] = input().split(" ")
s = input()

cnt = 0
init = (s[0]=='1')
h=[1]
h_cnt = 0

for i in range(1,n):
    if(s[i]!=s[i-1]):
        h_cnt+=1
        h.append(1)
    else:
        h[h_cnt]+=1

h_cnt+=1

zero_num = 0
ans = 0

if(init): #start with 1
    zero_num = h_cnt//2;
    if(zero_num<=k):
        ans = n
    else:
        sum_0 = sum(h[0:k*2+1])
        ans = sum_0
        for j in int range(0,zero_num-k+1): #j is 0's order
            sum_0 = sum_0 - h[j*2] - h[j*2+1] + h[(j+k)*2+1] + h[(j+k)*2+2]
            if(ans<=sum_0):
                ans = sum_0

else: #start with 0
    zero_num = h_cnt//2 +1;
    if(zero_num<=k):
        ans = n
    else:
        sum_0 = sum(h[0:k*2])
        ans = sum_0
        for j in range(0,zero_num-k+1): #j is 0's order
            sum_0 = sum_0 - h[j*2-1] - h[j*2] + h[(j+k)*2] + h[(j+k)*2+1]
            if(ans<=sum_0):
                ans = sum_0

printf(ans)

Fixed submission:
n,k = map(int, input().split())
s = input()
cnt = 0
init = (s[0]=='1')
h=[1]
h_cnt = 0

for i in range(1,n):
    if(s[i]!=s[i-1]):
        h_cnt+=1
        h.append(1)
    else:
        h[h_cnt]+=1

h_cnt+=1

zero_num = 0
ans = 0

if(init): #start with 1
    zero_num = h_cnt//2;
    if(zero_num<=k):
        ans = n
    else:
        sum_0 = sum(h[0:k*2+1])
        ans = sum_0
        h = h +[0,0,0]
        for j in range(0,zero_num-k): #j is 0's order
            sum_0 = sum_0 - h[j*2] - h[j*2+1] + h[(j+k)*2+1] + h[(j+k)*2+2]
            if(ans<=sum_0):
                ans = sum_0

else: #start with 0
    zero_num = h_cnt//2 +1;
    if(zero_num<=k):
        ans = n
    else:
        sum_0 = sum(h[0:k*2])
        ans = sum_0
        h = [0] + h +[0,0,0]
        for j in range(0,zero_num-k):#j is 0's order
            sum_0 = sum_0 - h[j*2] - h[j*2+1] + h[(j+k)*2+1] + h[(j+k)*2+2]
            if(ans<=sum_0):
                ans = sum_0

print(ans)