Buggy python submission (verdict: Runtime Error):
import numpy as np

def main(n,k,a):
  # Worst Case
  #n,k=100000,100
  #a=[p for p in range(100000)]
  
  kl=[p for p in range(1,k+1)]
  dp=[10**9]*(n)
  dp[0]=0
  for i in range(n):
    for j in kl:
      ij=i+j
      if ij < n:
        m=dp[i]+abs(a[i]-a[ij])
        if m < dp[ij]:
          dp[ij]=m
  print(dp[n-1])

def cc_export():
    from numba.pycc import CC
    cc = CC('my_module')
    cc.export('main','(i4,i4,i4[:])')(main)
    cc.compile()

if __name__ == '__main__':
    import sys
    if sys.argv[-1] == 'ONLINE_JUDGE':
    #if True:
      cc_export()
      exit(0)
    from my_module import main
    n,k=map(int,input().split())
    a=np.array(list(map(int,input().split())))    
    main(n,k,a)
    
    



Fixed submission:
n,k=map(int,input().split())
a=list(map(int,input().split()))
#n,k=100000,100
#a=[i for i in range(100000)]

kl=[i for i in range(1,k+1)]

dp=[float("inf")]*(n)
dp[0]=0
for i in range(1,n):
  dp[i] = min(dp[j] + abs(a[i] - a[j]) for j in range(max(0, i - k), i))

print(dp[n-1])

Buggy python submission (verdict: Runtime Error):
import numpy as np

def main(zz=0):
  # Worst Case
  #n,k=100000,100
  #a=[p for p in range(100000)]
  
  kl=[p for p in range(1,k+1)]
  dp=[10**9]*(n)
  dp[0]=0
  for i in range(n):
    for j in kl:
      ij=i+j
      if ij < n:
        m=dp[i]+abs(a[i]-a[ij])
        if m < dp[ij]:
          dp[ij]=m
  print(dp[n-1])

def cc_export():
    from numba.pycc import CC
    cc = CC('my_module')
    cc.export('main','(i4,)')(main)
    cc.compile()

    
if __name__ == '__main__':
    import sys
    if sys.argv[-1] == 'ONLINE_JUDGE':
        cc_export()
        exit(0)
    from my_module import main
    n,k=map(int,input().split())
    a=np.array(list(map(int,input().split())))
    main(0)


Fixed submission:
n,k=map(int,input().split())
a=list(map(int,input().split()))
#n,k=100000,100
#a=[i for i in range(100000)]

kl=[i for i in range(1,k+1)]

dp=[float("inf")]*(n)
dp[0]=0
for i in range(1,n):
  dp[i] = min(dp[j] + abs(a[i] - a[j]) for j in range(max(0, i - k), i))

print(dp[n-1])

Buggy python submission (verdict: Time Limit Exceeded):
from numba import njit,jit

@jit
def main():
  # Worst Case
  #n,k=100000,100
  #a=[p for p in range(100000)]
  
  kl=[p for p in range(1,k+1)]
  dp=[10**9]*(n)
  dp[0]=0
  for i in range(n):
    for j in kl:
      ij=i+j
      if ij < n:
        m=dp[i]+abs(a[i]-a[ij])
        if m < dp[ij]:
          dp[ij]=m

  print(dp[n-1])

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

Fixed submission:
n,k=map(int,input().split())
a=list(map(int,input().split()))
#n,k=100000,100
#a=[i for i in range(100000)]

kl=[i for i in range(1,k+1)]

dp=[float("inf")]*(n)
dp[0]=0
for i in range(1,n):
  dp[i] = min(dp[j] + abs(a[i] - a[j]) for j in range(max(0, i - k), i))

print(dp[n-1])

Buggy python submission (verdict: Time Limit Exceeded):
# 関数ラップするだけで倍近く早くなった…

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

def main():
  # Worst Case
  #n,k=100000,100
  #a=[p for p in range(100000)]
  
  kl=[p for p in range(1,k+1)]
  dp=[float("inf")]*(n)
  dp[0]=0
  for i in range(n):
    for j in kl:
      ij=i+j
      if ij < n:
        m=dp[i]+abs(a[i]-a[ij])
        if m < dp[ij]:
          dp[ij]=m

  print(dp[n-1])

main()

Fixed submission:
n,k=map(int,input().split())
a=list(map(int,input().split()))
#n,k=100000,100
#a=[i for i in range(100000)]

kl=[i for i in range(1,k+1)]

dp=[float("inf")]*(n)
dp[0]=0
for i in range(1,n):
  dp[i] = min(dp[j] + abs(a[i] - a[j]) for j in range(max(0, i - k), i))

print(dp[n-1])

Buggy python submission (verdict: Time Limit Exceeded):
n,k=map(int,input().split())
a=list(map(int,input().split()))
#n,k=100000,100
#a=[i for i in range(100000)]

kl=[i for i in range(1,k+1)]

dp=[float("inf")]*(n)
dp[0]=0
for i in range(n):
  for j in kl:
    ij=i+j
    if ij < n:
      m=dp[i]+abs(a[i]-a[ij])
      if m < dp[ij]:
        dp[ij]=m

print(dp[n-1])


Fixed submission:
n,k=map(int,input().split())
a=list(map(int,input().split()))
#n,k=100000,100
#a=[i for i in range(100000)]

kl=[i for i in range(1,k+1)]

dp=[float("inf")]*(n)
dp[0]=0
for i in range(1,n):
  dp[i] = min(dp[j] + abs(a[i] - a[j]) for j in range(max(0, i - k), i))

print(dp[n-1])