Buggy python submission (verdict: Runtime Error):
import sys
sys.setrecursionlimit(1000000)
N, K = map(int, input().split())
S = list(input())
X = []
cnt = 1
for i in range(1, N):
    if S[i] != S[i-1]:
        X.append(cnt)
        cnt = 0
    cnt += 1
    if i == N-1:
        X.append(cnt)

l = len(X)
if S[0] == '0' and (l+1)//2 <= k:
    print(N)
    exit()
if S[0] == '1' and l//2 <= k:
    print(N)
    exit()

ans = []
if S[0] == '1': 
    sum0 = sum(X[0:2*K+1])
    ans.append(sum0)
    i = 1
    while 2*K+2*i-1 < len(X):
        ans.append(ans[i-1] + X[2*K+2*i-1] + X[2*K+2*i] - X[2*i] - X[2*i-1])
        i += 1
else:
    sum0 = sum(X[0:2*K])
    ans.append(sum0)
    i = 1
    while 2*K+2*i <= len(X):
        if i == 1:
            ans.append(ans[i-1] + X[2*K+2*i-2] + X[2*K+2*i-1] - X[i-1])
            i += 1
        else:
            ans.append(ans[i-1] + X[2*K+2*i-2] + X[2*K+2*i-1] - X[2*i] - X[2*i-1])
            i += 1
print(max(ans))

Fixed submission:
N, K = map(int, input().split())
S = list(input())
X = []
cnt = 1
for i in range(1, N):
    if S[i] != S[i-1]:
        X.append(cnt)
        cnt = 0
    cnt += 1
    if i == N-1:
        X.append(cnt)
l = len(X)

if S[0] == '0' and (l+1)//2 <= K:
    print(N)
    exit()
if S[0] ==  '1' and l//2 <= K:
    print(N)
    exit()

ans = 0
result = 0
if S[0] == '0':
    for j in range(2*K):
        result += X[j]
    ans = result
    for j in range(2*K, l):
        if j == 2*K:
            result -= X[0]
        elif j%2 == 0:
            result = result - X[j-2*K] - X[j-2*K-1]
        result += X[j]
        ans = max(ans,result)
else:
    for j in range(2*K+1):
        result += X[j]
    ans = result
    for j in range(2*K+1, l):
        if j%2 == 1:
            result = result - X[j-2*K-1] - X[j -2*K]
        result += X[j]
        ans = max(ans, result)
print(ans)

Buggy python submission (verdict: Runtime Error):
import sys
sys.setrecursionlimit(1000000)
N, K = map(int, input().split())
S = list(input())
l = len(S)
X = []
cnt0 = 0
cnt1 = 0
for i in S:
    if i == '0':
        if cnt1 != 0:
            X.append(cnt1)
            cnt1 = 0
            cnt0 += 1
        else:
            cnt0 += 1
    else:
        if cnt0 != 0:
            X.append(cnt0)
            cnt0 = 0
            cnt1 += 1
        else:
            cnt1 += 1
if cnt1 != 0:
    X.append(cnt1)
elif cnt0 != 0:
    X.append(cnt0)
ans = []
if S[0] == '1': #Xの奇数は1
    sum0 = sum(X[0:2*K+1])
    ans.append(sum0)
    i = 1
    while 2*K+2*i-1 < len(X):
        ans.append(ans[i-1] + X[2*K+2*i-1] + X[2*K+2*i] - X[i] - X[i-1])
        i += 1
else:
    sum0 = sum(X[0:2*K])
    ans.append(sum0)
    i = 1
    while 2*K+2*i <= len(X):
        if i == 1:
            ans.append(ans[i-1] + X[2*K+2*i-2] + X[2*K+2*i-1] - X[i-1])
            i += 1
        else:
            ans.append(ans[i-1] + X[2*K+2*i-2] + X[2*K+2*i-1] - X[i] - X[i-1])
            i += 1
print(max(ans))

Fixed submission:
N, K = map(int, input().split())
S = list(input())
X = []
cnt = 1
for i in range(1, N):
    if S[i] != S[i-1]:
        X.append(cnt)
        cnt = 0
    cnt += 1
    if i == N-1:
        X.append(cnt)
l = len(X)

if S[0] == '0' and (l+1)//2 <= K:
    print(N)
    exit()
if S[0] ==  '1' and l//2 <= K:
    print(N)
    exit()

ans = 0
result = 0
if S[0] == '0':
    for j in range(2*K):
        result += X[j]
    ans = result
    for j in range(2*K, l):
        if j == 2*K:
            result -= X[0]
        elif j%2 == 0:
            result = result - X[j-2*K] - X[j-2*K-1]
        result += X[j]
        ans = max(ans,result)
else:
    for j in range(2*K+1):
        result += X[j]
    ans = result
    for j in range(2*K+1, l):
        if j%2 == 1:
            result = result - X[j-2*K-1] - X[j -2*K]
        result += X[j]
        ans = max(ans, result)
print(ans)

Buggy python submission (verdict: Runtime Error):
N, K = map(int, input().split())
S = list(input())
l = len(S)
X = []
cnt0 = 0
cnt1 = 0
for i in S:
    if i == '0':
        if cnt1 != 0:
            X.append(cnt1)
            cnt1 = 0
            cnt0 += 1
        else:
            cnt0 += 1
    else:
        if cnt0 != 0:
            X.append(cnt0)
            cnt0 = 0
            cnt1 += 1
        else:
            cnt1 += 1
if cnt1 != 0:
    X.append(cnt1)
elif cnt0 != 0:
    X.append(cnt0)
ans = []
if S[0] == '1': #Xの奇数は1
    sum0 = sum(X[0:2*K+1])
    ans.append(sum0)
    i = 1
    while 2*K+2*i-1 < len(X):
        ans.append(ans[i-1] + X[2*K+2*i-1] + X[2*K+2*i] - X[i] - X[i-1])
        i += 1
else:
    sum0 = sum(X[0:2*K])
    ans.append(sum0)
    i = 1
    while 2*K+2*i <= len(X):
        if i == 1:
            ans.append(ans[i-1] + X[2*K+2*i-2] + X[2*K+2*i-1] - X[i-1])
            i += 1
        else:
            ans.append(ans[i-1] + X[2*K+2*i-2] + X[2*K+2*i-1] - X[i] - X[i-1])
            i += 1
print(max(ans))

Fixed submission:
N, K = map(int, input().split())
S = list(input())
X = []
cnt = 1
for i in range(1, N):
    if S[i] != S[i-1]:
        X.append(cnt)
        cnt = 0
    cnt += 1
    if i == N-1:
        X.append(cnt)
l = len(X)

if S[0] == '0' and (l+1)//2 <= K:
    print(N)
    exit()
if S[0] ==  '1' and l//2 <= K:
    print(N)
    exit()

ans = 0
result = 0
if S[0] == '0':
    for j in range(2*K):
        result += X[j]
    ans = result
    for j in range(2*K, l):
        if j == 2*K:
            result -= X[0]
        elif j%2 == 0:
            result = result - X[j-2*K] - X[j-2*K-1]
        result += X[j]
        ans = max(ans,result)
else:
    for j in range(2*K+1):
        result += X[j]
    ans = result
    for j in range(2*K+1, l):
        if j%2 == 1:
            result = result - X[j-2*K-1] - X[j -2*K]
        result += X[j]
        ans = max(ans, result)
print(ans)

Buggy python submission (verdict: Runtime Error):
N, K = map(int, input().split())
S = list(input())
l = len(S)
X = []
cnt0 = 0
cnt1 = 0
for i in S:
    if i == '0':
        if cnt1 != 0:
            X.append(cnt1)
            cnt1 = 0
            cnt0 += 1
        else:
            cnt0 += 1
    else:
        if cnt0 != 0:
            X.append(cnt0)
            cnt0 = 0
            cnt1 += 1
        else:
            cnt1 += 1
if cnt1 != 0:
    X.append(cnt1)
elif cnt0 != 0:
    X.append(cnt0)
ans = []
if S[0] == '1': #Xの奇数は1
    sum0 = sum(X[0:2*K+1])
    ans.append(sum0)
    i = 1
    while 2*K+2*i-1 < len(X):
        ans.append(ans[i-1] + X[2*K+2*i-1] + X[2*K+2*i] - X[i] - X[i-1])
        i += 1
else:
    sum0 = sum(X[0:2*K])
    ans.append(sum0)
    i = 1
    while 2*K+2*i < len(X):
        if i == 1:
            ans.append(ans[i-1] + X[2*K+2*i+1] + X[2*K+2*i] - X[i-1])
            i += 1
        else:
            ans.append(ans[i-1] + X[2*K+2*i+1] + X[2*K+2*i] + X[i] - X[i] - X[i-1])
            i += 1
print(max(ans))

Fixed submission:
N, K = map(int, input().split())
S = list(input())
X = []
cnt = 1
for i in range(1, N):
    if S[i] != S[i-1]:
        X.append(cnt)
        cnt = 0
    cnt += 1
    if i == N-1:
        X.append(cnt)
l = len(X)

if S[0] == '0' and (l+1)//2 <= K:
    print(N)
    exit()
if S[0] ==  '1' and l//2 <= K:
    print(N)
    exit()

ans = 0
result = 0
if S[0] == '0':
    for j in range(2*K):
        result += X[j]
    ans = result
    for j in range(2*K, l):
        if j == 2*K:
            result -= X[0]
        elif j%2 == 0:
            result = result - X[j-2*K] - X[j-2*K-1]
        result += X[j]
        ans = max(ans,result)
else:
    for j in range(2*K+1):
        result += X[j]
    ans = result
    for j in range(2*K+1, l):
        if j%2 == 1:
            result = result - X[j-2*K-1] - X[j -2*K]
        result += X[j]
        ans = max(ans, result)
print(ans)

Buggy python submission (verdict: Runtime Error):
N, K = map(int, input().split())
S = list(input())
l = len(S)
X = []
cnt0 = 0
cnt1 = 0
for i in S:
    if i == '0':
        if cnt1 != 0:
            X.append(cnt1)
            cnt1 = 0
            cnt0 += 1
        else:
            cnt0 += 1
    else:
        if cnt0 != 0:
            X.append(cnt0)
            cnt0 = 0
            cnt1 += 1
        else:
            cnt1 += 1
if cnt1 != 0:
    X.append(cnt1)
elif cnt0 != 0:
    X.append(cnt0)
ans = []
if S[0] == '1': #Xの奇数は1
    sum0 = sum(X[0:2*K+1])
    ans.append(sum0)
    i = 1
    while 2*K+2*i-1 < len(X):
        ans.append(ans[i-1] + X[2*K+2*i-1] + X[2*K+2*i] - X[i] - X[i-1])
        i += 1
        print(ans)
else:
    sum0 = sum(X[0:2*K])
    ans.append(sum0)
    i = 1
    while 2*K+2*i < len(X):
        if i == 1:
            ans.append(ans[i-1] + X[2*K+2*i+1] + X[2*K+2*i] - X[i-1])
            i += 1
        else:
            ans.append(ans[i-1] + X[2*K+2*i+1] + X[2*K+2*i] + X[i] - X[i] - X[i-1])
            i += 1
print(max(ans))

Fixed submission:
N, K = map(int, input().split())
S = list(input())
X = []
cnt = 1
for i in range(1, N):
    if S[i] != S[i-1]:
        X.append(cnt)
        cnt = 0
    cnt += 1
    if i == N-1:
        X.append(cnt)
l = len(X)

if S[0] == '0' and (l+1)//2 <= K:
    print(N)
    exit()
if S[0] ==  '1' and l//2 <= K:
    print(N)
    exit()

ans = 0
result = 0
if S[0] == '0':
    for j in range(2*K):
        result += X[j]
    ans = result
    for j in range(2*K, l):
        if j == 2*K:
            result -= X[0]
        elif j%2 == 0:
            result = result - X[j-2*K] - X[j-2*K-1]
        result += X[j]
        ans = max(ans,result)
else:
    for j in range(2*K+1):
        result += X[j]
    ans = result
    for j in range(2*K+1, l):
        if j%2 == 1:
            result = result - X[j-2*K-1] - X[j -2*K]
        result += X[j]
        ans = max(ans, result)
print(ans)

Buggy python submission (verdict: Runtime Error):
N, K = map(int, input().split())
S = list(input())
l = len(S)
X = []
cnt0 = 0
cnt1 = 0
for i in S:
    if i == '0':
        if cnt1 != 0:
            X.append(cnt1)
            cnt1 = 0
            cnt0 += 1
        else:
            cnt0 += 1
    else:
        if cnt0 != 0:
            X.append(cnt0)
            cnt0 = 0
            cnt1 += 1
        else:
            cnt1 += 1
if cnt1 != 0:
    X.append(cnt1)
elif cnt0 != 0:
    X.append(cnt0)
ans = []
if S[0] == '1': #Xの奇数は1
    sum0 = sum(X[0:2*K+1])
    ans.append(sum0)
    i = 0
    if 2*K+1 >= len(X):
        ans = sum(X)
    else:
        while 2*K+i+1 < len(X):
            ans.append(ans[i] + X[2*K+i+1] - X[i])
            i += 1
else:
    sum0 = sum(X[0:2*K])
    ans.append(sum0)
    i = 0
    while 2*K+i < len(X):
        ans.append(ans[i] + X[2*K+i] - X[i])
        i += 1
print(max(ans))

Fixed submission:
N, K = map(int, input().split())
S = list(input())
X = []
cnt = 1
for i in range(1, N):
    if S[i] != S[i-1]:
        X.append(cnt)
        cnt = 0
    cnt += 1
    if i == N-1:
        X.append(cnt)
l = len(X)

if S[0] == '0' and (l+1)//2 <= K:
    print(N)
    exit()
if S[0] ==  '1' and l//2 <= K:
    print(N)
    exit()

ans = 0
result = 0
if S[0] == '0':
    for j in range(2*K):
        result += X[j]
    ans = result
    for j in range(2*K, l):
        if j == 2*K:
            result -= X[0]
        elif j%2 == 0:
            result = result - X[j-2*K] - X[j-2*K-1]
        result += X[j]
        ans = max(ans,result)
else:
    for j in range(2*K+1):
        result += X[j]
    ans = result
    for j in range(2*K+1, l):
        if j%2 == 1:
            result = result - X[j-2*K-1] - X[j -2*K]
        result += X[j]
        ans = max(ans, result)
print(ans)