Buggy python submission (verdict: Runtime Error):
from itertools import accumulate
N, K = map(int, input().split())
P = [i-1 for i in map(int, input().split())]
C = list(map(int, input().split()))

seen = [0] * N

ans = -10**20

for i in range(N):
    if not seen[i]:
        seen[i] = 1
        loop = [C[i]]
        while True:
            i = P[i]
            if seen[i]:
                break
            seen[i] = 1
            loop.append(C[i])
        L = len(loop)
        loop = loop + loop
        loop = [0] + list(accumulate(loop))
        if loop[L] <= 0:
            move = min(L, K)
            for i in range(L):
                for j in range(1, move + 1):
                    ans = max(ans, loop[i + j] - loop[i])
        else:
            if K > L:
                continue
                div, mod = divmod(K, L)
                tmp = div * loop[L]
                move = min(mod, L)
                if move:
                    for i in range(L):
                        for j in range(1, move + 1):
                            ans = max(ans, tmp + loop[i + j] - loop[i])
                else:
                    ans = max(ans, tmp)
                tmp = (div - 1) * loop[L]
                move = L
                for i in range(L):
                    for j in range(1, move + 1):
                        ans = max(ans, tmp + loop[i + j] - loop[i])
            else:
                move = K
                for i in range(L):
                    for j in range(1, move + 1):
                        ans = max(ans, tmp + loop[i + j] - loop[i])

print(ans)

Fixed submission:
from itertools import accumulate
N, K = map(int, input().split())
P = [i-1 for i in map(int, input().split())]
C = list(map(int, input().split()))

seen = [0] * N

ans = -10**20

for i in range(N):
    if not seen[i]:
        seen[i] = 1
        loop = [C[i]]
        while True:
            i = P[i]
            if seen[i]:
                break
            seen[i] = 1
            loop.append(C[i])
        L = len(loop)
        loop = loop + loop
        loop = [0] + list(accumulate(loop))
        if loop[L] <= 0:
            move = min(L, K)
            for i in range(L):
                for j in range(1, move + 1):
                    ans = max(ans, loop[i + j] - loop[i])
        else:
            if K > L:
                div, mod = divmod(K, L)
                tmp = div * loop[L]
                move = min(mod, L)
                if move:
                    for i in range(L):
                        for j in range(1, move + 1):
                            ans = max(ans, tmp + loop[i + j] - loop[i])
                else:
                    ans = max(ans, tmp)
                tmp = (div - 1) * loop[L]
                move = L
                for i in range(L):
                    for j in range(1, move + 1):
                        ans = max(ans, tmp + loop[i + j] - loop[i])
            else:
                move = K
                for i in range(L):
                    for j in range(1, move + 1):
                        ans = max(ans, loop[i + j] - loop[i])

print(ans)

Buggy python submission (verdict: Runtime Error):
from itertools import accumulate
N, K = map(int, input().split())
P = [i-1 for i in map(int, input().split())]
C = list(map(int, input().split()))

seen = [0] * N

ans = -10**20

for i in range(N):
    if not seen[i]:
        seen[i] = 1
        loop = [C[i]]
        while True:
            i = P[i]
            if seen[i]:
                break
            seen[i] = 1
            loop.append(C[i])
        L = len(loop)
        loop = loop + loop
        loop = [0] + list(accumulate(loop))
        if loop[L] <= 0:
            move = min(L, K)
            for i in range(L):
                for j in range(1, move + 1):
                    ans = max(ans, loop[i + j] - loop[i])
        else:
            if K > L:
                div, mod = divmod(K, L)
                tmp = div * loop[L]
                move = min(mod, L)
                if move:
                    for i in range(L):
                        for j in range(1, move + 1):
                            ans = max(ans, tmp + loop[i + j] - loop[i])
                else:
                    ans = max(ans, tmp)
                tmp = (div - 1) * loop[L]
                move = L
                for i in range(L):
                    for j in range(1, move + 1):
                        ans = max(ans, tmp + loop[i + j] - loop[i])
            else:
                move = K
                for i in range(L):
                    for j in range(1, move + 1):
                        ans = max(ans, tmp + loop[i + j] - loop[i])

print(ans)

Fixed submission:
from itertools import accumulate
N, K = map(int, input().split())
P = [i-1 for i in map(int, input().split())]
C = list(map(int, input().split()))

seen = [0] * N

ans = -10**20

for i in range(N):
    if not seen[i]:
        seen[i] = 1
        loop = [C[i]]
        while True:
            i = P[i]
            if seen[i]:
                break
            seen[i] = 1
            loop.append(C[i])
        L = len(loop)
        loop = loop + loop
        loop = [0] + list(accumulate(loop))
        if loop[L] <= 0:
            move = min(L, K)
            for i in range(L):
                for j in range(1, move + 1):
                    ans = max(ans, loop[i + j] - loop[i])
        else:
            if K > L:
                div, mod = divmod(K, L)
                tmp = div * loop[L]
                move = min(mod, L)
                if move:
                    for i in range(L):
                        for j in range(1, move + 1):
                            ans = max(ans, tmp + loop[i + j] - loop[i])
                else:
                    ans = max(ans, tmp)
                tmp = (div - 1) * loop[L]
                move = L
                for i in range(L):
                    for j in range(1, move + 1):
                        ans = max(ans, tmp + loop[i + j] - loop[i])
            else:
                move = K
                for i in range(L):
                    for j in range(1, move + 1):
                        ans = max(ans, loop[i + j] - loop[i])

print(ans)

Buggy python submission (verdict: Runtime Error):
from itertools import accumulate
N, K = map(int, input().split())
P = [i-1 for i in map(int, input().split())]
C = list(map(int, input().split()))

seen = [0] * N

ans = -10**20

for i in range(N):
    if not seen[i]:
        seen[i] = 1
        loop = [C[i]]
        while True:
            i = P[i]
            if seen[i]:
                break
            seen[i] = 1
            loop.append(C[i])
        L = len(loop)
        loop = [0] + list(accumulate(loop*2))
        if loop[L] <= 0:
            move = min(L, K)
            for i in range(L):
                for j in range(1, move+1):
                    ans = max(ans, loop[i + j] - loop[i])
        else:
            if K > L:
                div, mod = divmod(K, L)
                tmp = div * loop[L]
                move = min(mod, L)
                for i in range(L):
                    for j in range(1, move + 1):
                        ans = max(ans, tmp + loop[i + j] - loop[i])
                tmp = (div - 1) * loop[L]
                move = min(L, K)
                for i in range(L):
                    for j in range(1, move + 1):
                        ans = max(ans, tmp + loop[i + j] - loop[i])
            else:
                move = min(L, K)
                for i in range(L):
                    for j in range(1, move + 1):
                        ans = max(ans, tmp + loop[i + j] - loop[i])

print(ans)

Fixed submission:
from itertools import accumulate
N, K = map(int, input().split())
P = [i-1 for i in map(int, input().split())]
C = list(map(int, input().split()))

seen = [0] * N

ans = -10**20

for i in range(N):
    if not seen[i]:
        seen[i] = 1
        loop = [C[i]]
        while True:
            i = P[i]
            if seen[i]:
                break
            seen[i] = 1
            loop.append(C[i])
        L = len(loop)
        loop = loop + loop
        loop = [0] + list(accumulate(loop))
        if loop[L] <= 0:
            move = min(L, K)
            for i in range(L):
                for j in range(1, move + 1):
                    ans = max(ans, loop[i + j] - loop[i])
        else:
            if K > L:
                div, mod = divmod(K, L)
                tmp = div * loop[L]
                move = min(mod, L)
                if move:
                    for i in range(L):
                        for j in range(1, move + 1):
                            ans = max(ans, tmp + loop[i + j] - loop[i])
                else:
                    ans = max(ans, tmp)
                tmp = (div - 1) * loop[L]
                move = L
                for i in range(L):
                    for j in range(1, move + 1):
                        ans = max(ans, tmp + loop[i + j] - loop[i])
            else:
                move = K
                for i in range(L):
                    for j in range(1, move + 1):
                        ans = max(ans, loop[i + j] - loop[i])

print(ans)

Buggy python submission (verdict: Runtime Error):
from itertools import accumulate
N, K = map(int, input().split())
P = [i-1 for i in map(int, input().split())]
C = list(map(int, input().split()))

seen = [0] * N

ans = -10**20

for i in range(N):
    if not seen[i]:
        seen[i] = 1
        loop = [C[i]]
        while True:
            i = P[i]
            if seen[i]:
                break
            seen[i] = 1
            loop.append(C[i])
        L = len(loop)
        loop = [0]+list(accumulate(loop*2))
        if loop[L] <= 0:
            move = min(L, K)
            for i in range(L):
                for j in range(1, move+1):
                    ans = max(ans, loop[i+j]-loop[i])
        else:
            if K > L:
                div, mod = divmod(K, L)
                tmp = div * loop[L]
                move = min(mod, K)
                for i in range(L):
                    for j in range(1, move+1):
                        ans = max(ans, tmp + loop[i + j] - loop[i])
                tmp = (div - 1) * loop[L]
                move = min(L, K)
                for i in range(L):
                    for j in range(1, move + 1):
                        ans = max(ans, tmp + loop[i + j] - loop[i])
            else:
                move = min(L, K)
                for i in range(L):
                    for j in range(1, move + 1):
                        ans = max(ans, tmp + loop[i + j] - loop[i])

print(ans)

Fixed submission:
from itertools import accumulate
N, K = map(int, input().split())
P = [i-1 for i in map(int, input().split())]
C = list(map(int, input().split()))

seen = [0] * N

ans = -10**20

for i in range(N):
    if not seen[i]:
        seen[i] = 1
        loop = [C[i]]
        while True:
            i = P[i]
            if seen[i]:
                break
            seen[i] = 1
            loop.append(C[i])
        L = len(loop)
        loop = loop + loop
        loop = [0] + list(accumulate(loop))
        if loop[L] <= 0:
            move = min(L, K)
            for i in range(L):
                for j in range(1, move + 1):
                    ans = max(ans, loop[i + j] - loop[i])
        else:
            if K > L:
                div, mod = divmod(K, L)
                tmp = div * loop[L]
                move = min(mod, L)
                if move:
                    for i in range(L):
                        for j in range(1, move + 1):
                            ans = max(ans, tmp + loop[i + j] - loop[i])
                else:
                    ans = max(ans, tmp)
                tmp = (div - 1) * loop[L]
                move = L
                for i in range(L):
                    for j in range(1, move + 1):
                        ans = max(ans, tmp + loop[i + j] - loop[i])
            else:
                move = K
                for i in range(L):
                    for j in range(1, move + 1):
                        ans = max(ans, loop[i + j] - loop[i])

print(ans)

Buggy python submission (verdict: Runtime Error):
from itertools import accumulate
N, K = map(int, input().split())
P = [i-1 for i in map(int, input().split())]
C = list(map(int, input().split()))

seen = [0] * N

ans = -10**20

for i in range(N):
    if not seen[i]:
        seen[i] = 1
        loop = [C[i]]
        while True:
            i = P[i]
            if seen[i]:
                break
            seen[i] = 1
            loop.append(C[i])
        L = len(loop)
        loop = list(accumulate(loop*2, initial=0))
        if loop[L] <= 0:
            move = min(L, K)
            for i in range(L):
                for j in range(1, move+1):
                    ans = max(ans, loop[i+j]-loop[i])
        else:
            if K > L:
                div, mod = divmod(K, L)
                tmp = div * loop[L]
                move = min(mod, K)
                for i in range(L):
                    for j in range(1, move+1):
                        ans = max(ans, tmp + loop[i + j] - loop[i])
                tmp = (div - 1) * loop[L]
                move = min(L, K)
                for i in range(L):
                    for j in range(1, move + 1):
                        ans = max(ans, tmp + loop[i + j] - loop[i])
            else:
                move = min(L, K)
                for i in range(L):
                    for j in range(1, move + 1):
                        ans = max(ans, tmp + loop[i + j] - loop[i])

print(ans)

Fixed submission:
from itertools import accumulate
N, K = map(int, input().split())
P = [i-1 for i in map(int, input().split())]
C = list(map(int, input().split()))

seen = [0] * N

ans = -10**20

for i in range(N):
    if not seen[i]:
        seen[i] = 1
        loop = [C[i]]
        while True:
            i = P[i]
            if seen[i]:
                break
            seen[i] = 1
            loop.append(C[i])
        L = len(loop)
        loop = loop + loop
        loop = [0] + list(accumulate(loop))
        if loop[L] <= 0:
            move = min(L, K)
            for i in range(L):
                for j in range(1, move + 1):
                    ans = max(ans, loop[i + j] - loop[i])
        else:
            if K > L:
                div, mod = divmod(K, L)
                tmp = div * loop[L]
                move = min(mod, L)
                if move:
                    for i in range(L):
                        for j in range(1, move + 1):
                            ans = max(ans, tmp + loop[i + j] - loop[i])
                else:
                    ans = max(ans, tmp)
                tmp = (div - 1) * loop[L]
                move = L
                for i in range(L):
                    for j in range(1, move + 1):
                        ans = max(ans, tmp + loop[i + j] - loop[i])
            else:
                move = K
                for i in range(L):
                    for j in range(1, move + 1):
                        ans = max(ans, loop[i + j] - loop[i])

print(ans)