Buggy python submission (verdict: Runtime Error):
import sys
def main():
    n,k=map(int,input().split())
    arr=list(map(int,input().split()))
    dp=[-1 for i in range(n)]
    def solve(ind):
        if(ind==n-1):
            return 0
        if(dp[ind]!=-1):
            return dp[ind]
        ans=solve(ind+1)+abs(arr[ind+1]-arr[ind])
        for i in range(1,k+1):
            if(ind+i<n):
                ans=min(ans,solve(ind+i)+abs(arr[ind+i]-arr[ind]))
        dp[ind]=ans
        return dp[ind]
    print(solve(0))

py2 = round(0.5)
if py2:
    from future_builtins import ascii, filter, hex, map, oct, zip
 
    range = xrange
 
import os, sys
from io import IOBase, BytesIO
 
BUFSIZE = 8192
 
 
class FastIO(BytesIO):
    newlines = 0
 
    def __init__(self, file):
        self._file = file
        self._fd = file.fileno()
        self.writable = "x" in file.mode or "w" in file.mode
        self.write = super(FastIO, self).write if self.writable else None
 
    def _fill(self):
        s = os.read(self._fd, max(os.fstat(self._fd).st_size, BUFSIZE))
        self.seek((self.tell(), self.seek(0, 2), super(FastIO, self).write(s))[0])
        return s
 
    def read(self):
        while self._fill(): pass
        return super(FastIO, self).read()
 
    def readline(self):
        while self.newlines == 0:
            s = self._fill()
            self.newlines = s.count(b"\n") + (not s)
        self.newlines -= 1
        return super(FastIO, self).readline()
 
    def flush(self):
        if self.writable:
            os.write(self._fd, self.getvalue())
            self.truncate(0), self.seek(0)
 
 
class IOWrapper(IOBase):
    def __init__(self, file):
        self.buffer = FastIO(file)
        self.flush = self.buffer.flush
        self.writable = self.buffer.writable
        if py2:
            self.write = self.buffer.write
            self.read = self.buffer.read
            self.readline = self.buffer.readline
        else:
            self.write = lambda s: self.buffer.write(s.encode('ascii'))
            self.read = lambda: self.buffer.read().decode('ascii')
            self.readline = lambda: self.buffer.readline().decode('ascii')
 
 
sys.stdin, sys.stdout = IOWrapper(sys.stdin), IOWrapper(sys.stdout)
input = lambda: sys.stdin.readline().rstrip('\r\n')
if __name__ == '__main__':
    main()

Fixed submission:
n,k=map(int,input().split())
h=list(map(int,input().split()))
dp=[10**10 for i in range(n)]
dp[0]=0
dp[1]=abs(h[1]-h[0])
for i in range(2,n):
    for j in range(1,k+1):
        dp[i] = min(dp[i], dp[i-j] + abs(h[i] - h[i - j]))
print(dp[n-1])

Buggy python submission (verdict: Runtime Error):
#include<bits/stdc++.h>
using namespace std;
typedef long long 	ll;
const ll 	MOD		=  	1e+9+7;
const ll 	N 		= 	2*1e6;
int dp[10000001];
int arr[10000001];
int n,k;
int solve(int ind)
{
	if(ind==n-1)
	{
		return 0;
	}
	if(dp[ind]!=-1)
	{
		return dp[ind];
	}
	int ans=solve(ind+1)+abs(arr[ind+1]-arr[ind]);
	for(int i=1;i<=k;i++)
	{
		if(ind+i<n)
		{
			ans=min(ans,solve(ind+i)+abs(arr[ind+i]-arr[ind]));
		}
	}
	return dp[ind]=ans;

}
int main() {
#ifndef ONLINE_JUDGE
	freopen("input.txt","r",stdin);
	freopen("output.txt","w",stdout);
#endif
	memset(dp,-1,sizeof(dp));
	cin>>n>>k;
	for(int i=0;i<n;i++)
	{
		cin>>arr[i];
	}
	cout<<solve(0)<<"\n";
	
	return 0;
}

Fixed submission:
n,k=map(int,input().split())
h=list(map(int,input().split()))
dp=[10**10 for i in range(n)]
dp[0]=0
dp[1]=abs(h[1]-h[0])
for i in range(2,n):
    for j in range(1,k+1):
        dp[i] = min(dp[i], dp[i-j] + abs(h[i] - h[i - j]))
print(dp[n-1])