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

# ループを見つける(5000), 一周のスコアを確認
is_visit = [0 for _ in range(n)]
loop = []

def search(i, j):
    if is_visit[i] == 0:
        is_visit[i] = j
        l.append(i)
        search(p[i]-1, j)
    else:
        pass

loop_id = 1
for i in range(n):
    l = []
    search(i, loop_id)
    if len(l) != 0:
        loop.append(l)
        loop_id += 1
# print(loop)
# print(is_visit)

ans = [0 for _ in range(n)]
for i in range(n):
    # i からはじめて最大スコア
    l = loop[is_visit[i]-1] # 所属するループ
    tmp1 = 0 # ループによるスコア
    tmp_k = k
    s = 0
    for j in range(len(l)):
        s += c[l[j]]
    if s > 0 and k > len(l):
        # 回るほどお得で一周より回れる
        tmp1 += s*(tmp_k//len(l))
        tmp_k -= (tmp_k//len(l))*len(l)
    else:
        tmp_k -= (tmp_k//len(l))*len(l)
        if tmp_k == 0:
            tmp_k = len(l)
    pointer = p[i]
    tmp2 = [c[pointer-1] for _ in range(tmp_k)] # 愚直に進んだ点数
    if tmp_k != 0:
        for j in range(1, tmp_k):
            # k回目までの累積和で最大を求める
            pointer = p[pointer-1]
            tmp2[j] = tmp2[j-1] + c[pointer-1]
    # print(i, l, s, tmp_k, tmp1, tmp2)
    if len(tmp2) != 0:
        ans[i] = tmp1 + max(tmp2)
    else:
        ans[i] = tmp1
# print(ans)
print(max(ans))


Fixed submission:
import sys
sys.setrecursionlimit(2147483647)
n, k = map(int, input().split())
p = list(map(int, input().split()))
c = list(map(int, input().split()))

# ループを見つける(5000), 一周のスコアを確認
is_visit = [0 for _ in range(n)]
loop = []

def search(i, j):
    if is_visit[i] == 0:
        is_visit[i] = j
        l.append(i)
        search(p[i]-1, j)
    else:
        pass

loop_id = 1
for i in range(n):
    l = []
    search(i, loop_id)
    if len(l) != 0:
        loop.append(l)
        loop_id += 1
# print(loop)
# print(is_visit)
s_list = [0 for _ in range(len(loop))]
for i in range(len(s_list)):
    l = loop[i]
    s = 0
    for j in range(len(l)):
        s += c[l[j]]
    s_list[i] = s

ans = [0 for _ in range(n)]
for i in range(n):
    # i からはじめて最大スコア
    l = loop[is_visit[i]-1] # 所属するループ
    tmp1 = 0 # ループによるスコア
    tmp_k = k
    s = s_list[is_visit[i]-1]
    if s > 0 and k > len(l):
        # 回るほどお得で一周より回れる
        tmp1 += s*(tmp_k//len(l)-1)
        tmp_k -= (tmp_k//len(l)-1)*len(l)
    elif s <= 0 and k > len(l):
        tmp_k -= (tmp_k//len(l)-1)*len(l)
        if tmp_k == 0:
            tmp_k = len(l)
    pointer = p[i]
    tmp2 = [c[pointer-1] for _ in range(tmp_k)] # 愚直に進んだ点数
    if tmp_k != 0:
        for j in range(1, tmp_k):
            # k回目までの累積和で最大を求める
            pointer = p[pointer-1]
            tmp2[j] = tmp2[j-1] + c[pointer-1]
    # print(i, l, s, tmp_k, tmp1, tmp2)
    if len(tmp2) != 0:
        ans[i] = tmp1 + max(tmp2)
    else:
        ans[i] = tmp1
# print(ans)
print(max(ans))

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

# ループを見つける(5000), 一周のスコアを確認
is_visit = [0 for _ in range(n)]
loop = []

def search(i, j):
    if is_visit[i] == 0:
        is_visit[i] = j
        l.append(i)
        search(p[i]-1, j)

loop_id = 1
for i in range(n):
    l = []
    search(i, loop_id)
    if len(l) != 0:
        loop.append(l)
        loop_id += 1
# print(loop)
# print(is_visit)

ans = [0 for _ in range(n)]
for i in range(n):
    # i からはじめて最大スコア
    l = loop[is_visit[i]-1] # 所属するループ
    tmp1 = 0 # ループによるスコア
    tmp_k = k
    s = 0
    for j in range(len(l)):
        s += c[l[j]]
    if s > 0 and k > len(l):
        # 回るほどお得
        tmp1 += s*(tmp_k//len(l))
        tmp_k -= tmp_k//len(l)*len(l)
    else:
        tmp_k -= tmp_k//len(l)*len(l)
        if tmp_k == 0:
            tmp_k = len(l)
    pointer = p[i]
    tmp2 = [c[pointer-1] for _ in range(tmp_k)] # 愚直に進んだ点数
    if tmp_k != 0:
        for j in range(1, tmp_k):
            # k回目までの累積和で最大を求める
            pointer = p[pointer-1]
            tmp2[j] = tmp2[j-1] + c[pointer-1]
    # print(i, l, s, tmp_k, tmp1, tmp2)
    ans[i] = tmp1 + max(tmp2)
# print(ans)
print(max(ans))


Fixed submission:
import sys
sys.setrecursionlimit(2147483647)
n, k = map(int, input().split())
p = list(map(int, input().split()))
c = list(map(int, input().split()))

# ループを見つける(5000), 一周のスコアを確認
is_visit = [0 for _ in range(n)]
loop = []

def search(i, j):
    if is_visit[i] == 0:
        is_visit[i] = j
        l.append(i)
        search(p[i]-1, j)
    else:
        pass

loop_id = 1
for i in range(n):
    l = []
    search(i, loop_id)
    if len(l) != 0:
        loop.append(l)
        loop_id += 1
# print(loop)
# print(is_visit)
s_list = [0 for _ in range(len(loop))]
for i in range(len(s_list)):
    l = loop[i]
    s = 0
    for j in range(len(l)):
        s += c[l[j]]
    s_list[i] = s

ans = [0 for _ in range(n)]
for i in range(n):
    # i からはじめて最大スコア
    l = loop[is_visit[i]-1] # 所属するループ
    tmp1 = 0 # ループによるスコア
    tmp_k = k
    s = s_list[is_visit[i]-1]
    if s > 0 and k > len(l):
        # 回るほどお得で一周より回れる
        tmp1 += s*(tmp_k//len(l)-1)
        tmp_k -= (tmp_k//len(l)-1)*len(l)
    elif s <= 0 and k > len(l):
        tmp_k -= (tmp_k//len(l)-1)*len(l)
        if tmp_k == 0:
            tmp_k = len(l)
    pointer = p[i]
    tmp2 = [c[pointer-1] for _ in range(tmp_k)] # 愚直に進んだ点数
    if tmp_k != 0:
        for j in range(1, tmp_k):
            # k回目までの累積和で最大を求める
            pointer = p[pointer-1]
            tmp2[j] = tmp2[j-1] + c[pointer-1]
    # print(i, l, s, tmp_k, tmp1, tmp2)
    if len(tmp2) != 0:
        ans[i] = tmp1 + max(tmp2)
    else:
        ans[i] = tmp1
# print(ans)
print(max(ans))

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

# ループを見つける(5000), 一周のスコアを確認
is_visit = [0 for _ in range(n)]
loop = []

def search(i, j):
    if is_visit[i] == 0:
        is_visit[i] = j
        l.append(i)
        search(p[i]-1, j)

loop_id = 1
for i in range(n):
    l = []
    search(i, loop_id)
    if len(l) != 0:
        loop.append(l)
        loop_id += 1
# print(loop)
# print(is_visit)

ans = [0 for _ in range(n)]
for i in range(n):
    # i からはじめて最大スコア
    l = loop[is_visit[i]-1] # 所属するループ
    tmp1 = 0 # ループによるスコア
    tmp_k = k
    s = 0
    for j in range(len(l)):
        s += c[l[j]]
    if s > 0 and k > len(l):
        # 回るほどお得
        tmp1 += s*(tmp_k//len(l))
        tmp_k -= tmp_k//len(l)*len(l)
    else:
        tmp_k -= tmp_k//len(l)*len(l)
        if tmp_k == 0:
            tmp_k = len(l)
    pointer = p[i]
    tmp2 = [c[pointer-1] for _ in range(tmp_k)] # 愚直に進んだ点数
    if tmp_k != 0:
        for j in range(1, tmp_k):
            # k回目までの累積和で最大を求める
            pointer = p[pointer-1]
            tmp2[j] = tmp2[j-1] + c[pointer-1]
    # print(i, l, s, tmp_k, tmp1, tmp2)
    if len(tmp2) != 0:
        ans[i] = tmp1 + max(tmp2)
    else:
        ans[i] = tmp1
# print(ans)
print(max(ans))


Fixed submission:
import sys
sys.setrecursionlimit(2147483647)
n, k = map(int, input().split())
p = list(map(int, input().split()))
c = list(map(int, input().split()))

# ループを見つける(5000), 一周のスコアを確認
is_visit = [0 for _ in range(n)]
loop = []

def search(i, j):
    if is_visit[i] == 0:
        is_visit[i] = j
        l.append(i)
        search(p[i]-1, j)
    else:
        pass

loop_id = 1
for i in range(n):
    l = []
    search(i, loop_id)
    if len(l) != 0:
        loop.append(l)
        loop_id += 1
# print(loop)
# print(is_visit)
s_list = [0 for _ in range(len(loop))]
for i in range(len(s_list)):
    l = loop[i]
    s = 0
    for j in range(len(l)):
        s += c[l[j]]
    s_list[i] = s

ans = [0 for _ in range(n)]
for i in range(n):
    # i からはじめて最大スコア
    l = loop[is_visit[i]-1] # 所属するループ
    tmp1 = 0 # ループによるスコア
    tmp_k = k
    s = s_list[is_visit[i]-1]
    if s > 0 and k > len(l):
        # 回るほどお得で一周より回れる
        tmp1 += s*(tmp_k//len(l)-1)
        tmp_k -= (tmp_k//len(l)-1)*len(l)
    elif s <= 0 and k > len(l):
        tmp_k -= (tmp_k//len(l)-1)*len(l)
        if tmp_k == 0:
            tmp_k = len(l)
    pointer = p[i]
    tmp2 = [c[pointer-1] for _ in range(tmp_k)] # 愚直に進んだ点数
    if tmp_k != 0:
        for j in range(1, tmp_k):
            # k回目までの累積和で最大を求める
            pointer = p[pointer-1]
            tmp2[j] = tmp2[j-1] + c[pointer-1]
    # print(i, l, s, tmp_k, tmp1, tmp2)
    if len(tmp2) != 0:
        ans[i] = tmp1 + max(tmp2)
    else:
        ans[i] = tmp1
# print(ans)
print(max(ans))