求问为什么我的E写的也是O(6nk)，但是超时呀，毫无思路优化

from math import inf


n, k = list(map(int, input().split(" ")))
a = list(map(int, input().split(" ")))

dp = [[-inf] * (k + 1) for _ in range(n)]
# dp[i][j], 当前在i, 跳了j次的最大余额

for i in range(6):
    dp[i][1] = a[i]

for i in range(n):
    for j in range(k):  # 仅到k - 1
        if not dp[i][j] > -inf:
            continue
        for offset in range(1, 6 + 1):
            if i + offset >= n:
                break
            dp[i + offset][j + 1] = max(dp[i + offset][j + 1], dp[i][j] + a[i + offset])

print(max([dp[i][k] for i in range(n)]))