public class Main {
    public static void main(String[] args) {
        int n = 6;
        long k = 3;
        long[] b = {0, 10, 30, 20, 50, 40, 60}; 
 
        long[] dp = new long[n + 1];
        for (int i = 1; i <= n; i++) {
            dp[i] = Long.MAX_VALUE;
        }
 
        dp[1] = 0;
        dp[2] = Math.abs(b[1] - b[2]);
 
        for (int i = 3; i <= n; i++) {
            for (int j = 1; j <= k && i - j >= 1; j++) {
                dp[i] = Math.min(dp[i], dp[i - j] + Math.abs(b[i] - b[i - j]));
            }
        }
 
        System.out.println("Minimum cost to reach last step: " + dp[n]);
    }
}
 

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