Create array2.java

[Praniksha123]

No description provided.

[super30admin]

Find All Numbers Disappeared in an Array (array2.java)

Strengths:

• Excellent use of the in-place marking technique that achieves O(n) time complexity
• Properly handles negative values using Math.abs() to avoid breaking the algorithm
• Clean, readable code with good variable naming
• Comprehensive comments explaining the approach
• The Game of Life solution correctly implements the temporary state technique

Areas for Improvement:

• The solution file is named "array2.java" - consider more descriptive naming like "FindDisappearedNumbers.java"
• Could add input validation for edge cases (though constraints guarantee valid input)
• The Game of Life helper method name "gameoflife" could be more descriptive (e.g., "countLiveNeighbors")
• Consider adding a brief explanation of why the output list doesn't count as extra space in the comments

Comparison to Reference:

• Student's solution is significantly more efficient (O(n) vs O(n²))
• Both achieve O(1) space complexity (excluding output)
• Student's approach is the optimal solution for this problem

VERDICT: PASS

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max and min

Major Issue: You submitted solutions for the wrong problems. The problem statement clearly asks to find minimum and maximum values in an array using fewer than 2*(N-2) comparisons. Your code solves "Find Disappeared Numbers" and "Game of Life" instead.

What you should do:

1. Carefully read the problem statement before submitting
2. Understand the reference solution's approach: it processes elements in pairs, making only 3 comparisons per pair (instead of 4 comparisons if done separately)
3. For the min/max problem, the optimal approach is to compare pairs internally first, then compare the smaller elements for min and larger elements for max

Strengths of your submitted code:

• Your Game of Life solution correctly uses in-place state transitions (2 and 3 as intermediate states)
• Your disappeared numbers solution properly uses the marking technique with Math.abs()
• Both solutions have O(1) space complexity as required

Areas for improvement:

• Always match your solution to the exact problem being asked
• For the min/max problem, you would need to implement a pairwise comparison algorithm

VERDICT: NEEDS_IMPROVEMENT

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Game of Life

Strengths:

• Correctly implements the in-place algorithm using temporary states
• Properly counts neighbors considering both original alive cells and those marked for death
• Handles boundary conditions correctly with bounds checking
• Follows the same efficient approach as the reference solution

Areas for Improvement:

1. Remove the unrelated problem solution from the file - only submit code for the specific problem asked
2. The neighbor counting logic is correct but could be more readable with better variable names (e.g., newRow/newCol instead of nr/dn)
3. Consider extracting the direction array as a class-level constant to avoid recreating it for each cell
4. The second pass could use if-else instead of two separate if statements for clarity
5. Add comments explaining the temporary state encoding (2 and 3) for future maintainability

Time Complexity: O(m*n) - same as reference ✓
Space Complexity: O(1) - same as reference ✓

VERDICT: PASS