Buggy python submission (verdict: Runtime Error):
import sys

def main():
  n, k, *h = map(int, sys.stdin.read().split())
  dp = [float("inf")] * n
  dp[0] = 0
  for i in range(1, n):
    if i < k:
      dp[i] = min([ dpj+abs(hj-h[i]) for dpj, hj in zip(dp[:i], h[:i]) ])
    else:
      dp[i] = min( [ dpj+abs(hj-h[i]) for dpj, hj in zip(dp[i-k:k], h[i-k:k]) ] )
  print(dp[n-1])
  
if __name__ == "__main__":
  main()

Fixed submission:
n, k = map(int, input().split())
h = list(map(int, input().split()))
dp = [float("inf")] * n
dp[0] = 0
for i in range(1, n):
  if i < k:
    dp[i] = min([ dp[j]+abs(h[j]-h[i]) for j in range(i) ])
  else:
    dp[i] = min( [ dp[i-j-1]+abs(h[i-j-1]-h[i]) for j in range(k) ] )
print(dp[n-1])

Buggy python submission (verdict: Time Limit Exceeded):
import sys

def main():
  n, k, *h = map(int, sys.stdin.read().split())
  dp = [float("inf")] * n
  dp[0] = 0
  for i in range(1, n):
    if i < k:
      dp[i] = min([ dp[j]+abs(h[j]-h[i]) for j in range(i) ])
    else:
      dp[i] = min( [ dp[i-j-1]+abs(h[i-j-1]-h[i]) for j in range(k) ] )
  print(dp[n-1])
  
if __name__ == "__main__":
  main()

Fixed submission:
n, k = map(int, input().split())
h = list(map(int, input().split()))
dp = [float("inf")] * n
dp[0] = 0
for i in range(1, n):
  if i < k:
    dp[i] = min([ dp[j]+abs(h[j]-h[i]) for j in range(i) ])
  else:
    dp[i] = min( [ dp[i-j-1]+abs(h[i-j-1]-h[i]) for j in range(k) ] )
print(dp[n-1])

Buggy python submission (verdict: Time Limit Exceeded):
import sys
input = sys.stdin.readline

def main():
  n, k = map(int, input().split())
  h = list(map(int, input().split()))
  dp = [float("inf")] * n
  dp[0] = 0
  for i in range(1, n):
    if i < k:
      dp[i] = min([ dp[j]+abs(h[j]-h[i]) for j in range(i) ])
    else:
      dp[i] = min( [ dp[i-j-1]+abs(h[i-j-1]-h[i]) for j in range(k) ] )
  print(dp[n-1])
  
if __name__ == "__main__":
  main()

Fixed submission:
n, k = map(int, input().split())
h = list(map(int, input().split()))
dp = [float("inf")] * n
dp[0] = 0
for i in range(1, n):
  if i < k:
    dp[i] = min([ dp[j]+abs(h[j]-h[i]) for j in range(i) ])
  else:
    dp[i] = min( [ dp[i-j-1]+abs(h[i-j-1]-h[i]) for j in range(k) ] )
print(dp[n-1])

Buggy python submission (verdict: Time Limit Exceeded):
n, k = map(int, input().split())
h = list(map(int, input().split()))
dp = [float("inf")] * n
dp[0] = 0
for i in range(1, n):
  if i < k:
    dp[i] = min( { dp[j]+abs(h[j]-h[i]) for j in range(i) } )
  else:
    dp[i] = min( { dp[i-j-1]+abs(h[i-j-1]-h[i]) for j in range(k) } )
print(dp[n-1])

Fixed submission:
n, k = map(int, input().split())
h = list(map(int, input().split()))
dp = [float("inf")] * n
dp[0] = 0
for i in range(1, n):
  if i < k:
    dp[i] = min([ dp[j]+abs(h[j]-h[i]) for j in range(i) ])
  else:
    dp[i] = min( [ dp[i-j-1]+abs(h[i-j-1]-h[i]) for j in range(k) ] )
print(dp[n-1])

Buggy python submission (verdict: Time Limit Exceeded):
n, k = map(int, input().split())
h = list(map(int, input().split()))
dp = [float("inf")] * n
dp[0] = 0
for i in range(1, n):
  if i < k:
    dp[i] = min([ dp[j]+abs(h[j]-h[i]) for j in range(i) ])
  else:
    dp[i] = min( [ dp[i-j-1]+abs(h[i-j-1]-h[i]) for j in range(k) ] )
print(dp[n-1])

Fixed submission:
n, k = map(int, input().split())
h = list(map(int, input().split()))
dp = [float("inf")] * n
dp[0] = 0
for i in range(1, n):
  if i < k:
    dp[i] = min([ dp[j]+abs(h[j]-h[i]) for j in range(i) ])
  else:
    dp[i] = min( [ dp[i-j-1]+abs(h[i-j-1]-h[i]) for j in range(k) ] )
print(dp[n-1])