Hashing-2 solution

[Simranb10]

No description provided.

[super30admin]

Subarray Sum Equals K (SubArraySum.java)

Great job! Your solution correctly implements the optimal prefix sum + HashMap approach for this problem. The logic is sound, and you've handled the edge case of subarrays starting from index 0 by initializing the map with 0 -> 1.

A few minor suggestions to improve code quality:

1. You can simplify the map update logic using getOrDefault:

   map.put(sum, map.getOrDefault(sum, 0) + 1);

   This is more concise and idiomatic Java.

2. Consider adding comments to explain the key insight (why we look for sum - k in the map) for future readers.

3. The variable name curr could be more descriptive, like targetPrefixSum or neededSum.

Overall, this is a solid solution that demonstrates a good understanding of the problem and the optimal approach.

VERDICT: PASS

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Contiguous Array (ContiguousArray.java)

Excellent work! Your solution is correct, efficient, and well-implemented. Here are some observations:

Strengths:

• Your solution correctly implements the running sum technique with the clever insight of treating 0s as -1 and 1s as +1
• The initialization with count.put(0, -1) is correctly handled to account for subarrays starting from index 0
• Using Map<Integer, Integer> interface instead of concrete HashMap is a good practice (dependency inversion)
• The code is clean, readable, and well-commented with complexity analysis
• Time and space complexity match the optimal solution

Minor suggestions for improvement:

• Consider adding a brief comment explaining the algorithm approach (e.g., "Treat 0 as -1 and 1 as +1, then find longest subarray with sum 0")
• The variable name count could be more descriptive - perhaps sumIndexMap would better convey its purpose
• Consider edge case handling: what if nums is null or empty? (Though this may not be required by the problem constraints)

Overall, this is a high-quality solution that demonstrates a strong understanding of the problem and the optimal approach.

VERDICT: PASS

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Longest Palindrome (LongestPalindrome.java)

E.g., Format:
VERtdICT: NEEDS_IMPROVEMENT

VERDICT: PASS