Source code
public class VanEckSequence {
public static void main(String[] args) {
int[] seq = new int[1000];
seq[0] = 0;
for (int i = 1; i < seq.length; i++) {
int last = seq[i-1];
int prev = -1;
for (int j = i-2; j >= 0; j--) {
if (seq[j] == last) {
prev = j;
break;
}
}
if (prev == -1) {
seq[i] = 0;
} else {
seq[i] = i-1-prev;
}
System.out.println(seq[i]);
}
}
}
Run 1
The code is logically structured with clear variable names (seq, last, prev) and simple loops, making it easy to follow. Nesting is only two levels deep, which is acceptable. The intent is mostly clear—generate the Van Eck sequence—but the inner search loop could be more self-explanatory. Code length is concise for the task. Action granularity is mixed: variable declarations and assignments are mostly one per line, but the System.out.println inside the loop may be a side effect that reduces clarity. Reading flow is natural overall, but the search for the previous occurrence could be refactored into a separate method with a descriptive name to improve clarity of intent and structure.
Run 2
The code is concise and follows a straightforward structure, with a single class and method. The nested loops are logically organized and the use of 'break' avoids unnecessary iteration. Variables are somewhat clear, though 'prev' could be more descriptive. The logic is understandable but assumes familiarity with the Van Eck sequence; a brief comment would improve clarity. The code is flat, with only two nested loops, and each line performs a single action, aiding readability. However, the inner loop and conditional block could be extracted for improved clarity. Overall, it is readable and efficient, but could benefit from minor naming improvements and comments.
Run 3
The code is generally readable and well-structured. The class and method structure are clear, and the algorithm is implemented with straightforward logic. The nesting is shallow (2 levels), and the intent is fairly clear for someone familiar with the Van Eck sequence concept. Variable names like 'last' and 'prev' are meaningful. However, there are minor readability issues: the 'prev' variable uses -1 as a sentinel value without explanation, and the inner loop's purpose could be clarified with a comment or helper method. The code is concise but slightly terse. The action granularity is mostly one action per line, and the reading flow is natural. Overall, it's a solid implementation that would benefit from brief comments.
Run 1
Code Structure: Logically organized into initialization, sequence generation, backward search, and output. Nesting: Moderate nesting from two loops and a conditional remains easy to follow. Clarity of intent: The class name identifies the sequence, and variable names are reasonable, though the recurrence and -1 sentinel would benefit from brief explanation. Code length: Concise, with no unnecessary abstractions or repetition. Action granularity: Each statement performs a single clear action. Reading flow: Execution proceeds naturally, but missing spaces around arithmetic operators and no separation between logical stages slightly reduce readability. Printing begins at index 1, leaving the initialized first element unprinted, which makes the output intent slightly unclear.
Run 2
Code Structure: Logically organized into initialization, sequence generation, backward search, and output. Nesting: Moderate nesting from two loops and a conditional, but easy to follow. Clarity of intent: The class name identifies the sequence, and variable names are understandable, though the recurrence and -1 sentinel could benefit from explanation. Code length: Concise, with no unnecessary machinery. Action granularity: Statements generally perform one action per line. Reading flow: Natural top-to-bottom progression, although missing spaces around arithmetic operators slightly reduce readability. Printing starts at the second term while the first term is initialized silently, which leaves the intended output somewhat unclear.
Run 3
Code Structure: The sequence generation is logically organized into initialization, backward search, value calculation, and output. Nesting: The nested loop and conditional introduce moderate depth, but remain easy to follow. Clarity of intent: The class name identifies the sequence, and the algorithm is understandable, though abbreviated variable names and the unexplained -1 sentinel require some interpretation. Code length: The implementation is concise without unnecessary machinery. Action granularity: Each statement performs a single action, making execution straightforward to trace. Reading flow: Control flow is natural and sequential; consistent spacing around arithmetic operators and a brief algorithm comment would improve readability. Printing within the generation loop slightly mixes responsibilities, and omitting the initial element from output may make the intended output less clear.