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Caution Review failedThe pull request is closed. WalkthroughThis pull request introduces a new LeetCode problem solution for Problem 322 (Coin Change). It adds documentation, two dynamic programming implementations (naive and optimized), parameterized test utilities, and updates the README with the new problem entry and references. Changes
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Actionable comments posted: 4
🧹 Nitpick comments (2)
src/main/java/codes/yam/leetcode/coinchange/SolutionDpNaive.java (1)
4-5: Redundantamount == 0guard — the general logic handles this correctly.
dp[0]defaults to0, the loop bodyfor (int a = 1; a <= 0; ...)never executes, anddp[0]is returned. The early return adds noise without defensive value.♻️ Proposed simplification
int coinChange(int[] coins, int amount) { - if (amount == 0) return 0; int[] dp = new int[amount + 1];🤖 Prompt for AI Agents
Verify each finding against the current code and only fix it if needed. In `@src/main/java/codes/yam/leetcode/coinchange/SolutionDpNaive.java` around lines 4 - 5, Remove the redundant early return in coinChange: delete the "if (amount == 0) return 0;" guard in SolutionDpNaive.coinChange and rely on the existing dp array logic (ensure dp is sized amount+1 with dp[0] == 0, the for loop from a = 1..amount will skip when amount==0, and the final return logic using dp[amount] stays unchanged).src/test/java/codes/yam/leetcode/coinchange/TestCases.java (1)
8-13: LGTM — three well-chosen scenarios covering the key paths.Consider adding a case where no coin divides the amount (already covered by
[2]/3 → -1) and one where a coin exactly equalsamount(coins=[11], amount=11 → 1) to reinforce thec == apath tested specifically bySolutionDpNaive.🤖 Prompt for AI Agents
Verify each finding against the current code and only fix it if needed. In `@src/test/java/codes/yam/leetcode/coinchange/TestCases.java` around lines 8 - 13, Add a test case to cover the path where a coin exactly equals the amount by updating the TestCases.cases() Stream to include Arguments.of(new int[] {11}, 11, 1); this ensures the SolutionDpNaive/c == a branch is exercised; simply append that Arguments.of entry alongside the existing cases in the Stream.of(...) list.
🤖 Prompt for all review comments with AI agents
Verify each finding against the current code and only fix it if needed.
Inline comments:
In `@README.md`:
- Line 14: Update the README table row for lc-322 / SolutionDp to replace both
"TBD" entries with the correct complexities: set Time to "O(amount × n) where n
= coins.length" and set Space to "O(amount)"; locate the table row referencing
SolutionDp (Coin Change) and edit the Time and Space columns accordingly so they
match the other rows' format.
In `@src/main/java/codes/yam/leetcode/coinchange/SolutionDp.java`:
- Line 5: The file defines class SolutionDp but the repository requires a
canonical Solution.java for the optimal solution; either rename the file and
class from SolutionDp to Solution (i.e., change class SolutionDp -> Solution and
the filename SolutionDp.java -> Solution.java) or create a new Solution.java
that forwards to or contains the implementation in SolutionDp (for example by
copying the implementation or delegating calls to SolutionDp), ensuring the
package and public class name are exactly Solution so the canonical entrypoint
exists alongside any SolutionDp variant.
- Around line 5-20: Add an HTML-formatted Javadoc block immediately above the
class declaration for SolutionDp describing the class and include explicit `@Time`
Complexity and `@Space` Complexity tags (e.g., "Time Complexity: O(amount *
coins.length)" and "Space Complexity: O(amount)") documenting the
coinChange(int[] coins, int amount) DP solution; ensure the Javadoc uses
standard HTML tags and adheres to the package-scoped Solution*.java guidelines.
In `@src/main/java/codes/yam/leetcode/coinchange/SolutionDpNaive.java`:
- Line 3: Add an HTML-formatted Javadoc block immediately above the class
declaration for SolutionDpNaive that documents the algorithm and includes
explicit "Time Complexity" and "Space Complexity" lines (e.g., using <p> or <b>
tags to label them) so the class follows the project guideline for Solution*
classes; keep the class package-scoped and retain the existing class name
SolutionDpNaive while filling in the accurate Big-O complexities for the
implemented DP naive coin change approach.
---
Nitpick comments:
In `@src/main/java/codes/yam/leetcode/coinchange/SolutionDpNaive.java`:
- Around line 4-5: Remove the redundant early return in coinChange: delete the
"if (amount == 0) return 0;" guard in SolutionDpNaive.coinChange and rely on the
existing dp array logic (ensure dp is sized amount+1 with dp[0] == 0, the for
loop from a = 1..amount will skip when amount==0, and the final return logic
using dp[amount] stays unchanged).
In `@src/test/java/codes/yam/leetcode/coinchange/TestCases.java`:
- Around line 8-13: Add a test case to cover the path where a coin exactly
equals the amount by updating the TestCases.cases() Stream to include
Arguments.of(new int[] {11}, 11, 1); this ensures the SolutionDpNaive/c == a
branch is exercised; simply append that Arguments.of entry alongside the
existing cases in the Stream.of(...) list.
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| import java.util.Arrays; | ||
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| class SolutionDp { |
There was a problem hiding this comment.
🛠️ Refactor suggestion | 🟠 Major
SolutionDp should be Solution.java — the canonical final/optimal solution file is missing.
The guidelines require each problem package to contain a Solution.java as the final/optimal solution, with additional variants as Solution*.java. Currently SolutionDp.java plays the role of the optimal solution (as documented in package-info.java), but no Solution.java exists. Either rename SolutionDp.java → Solution.java, or add a dedicated Solution.java that contains the optimal implementation.
As per coding guidelines, src/main/java/codes/yam/leetcode/**/*.java: "Each LeetCode problem should live in its own package under codes.yam.leetcode with Solution.java as the final/optimal solution and additional solutions prefixed with Solution*."
🤖 Prompt for AI Agents
Verify each finding against the current code and only fix it if needed.
In `@src/main/java/codes/yam/leetcode/coinchange/SolutionDp.java` at line 5, The
file defines class SolutionDp but the repository requires a canonical
Solution.java for the optimal solution; either rename the file and class from
SolutionDp to Solution (i.e., change class SolutionDp -> Solution and the
filename SolutionDp.java -> Solution.java) or create a new Solution.java that
forwards to or contains the implementation in SolutionDp (for example by copying
the implementation or delegating calls to SolutionDp), ensuring the package and
public class name are exactly Solution so the canonical entrypoint exists
alongside any SolutionDp variant.
| class SolutionDp { | ||
| int coinChange(int[] coins, int amount) { | ||
| int[] dp = new int[amount + 1]; | ||
| Arrays.fill(dp, 1, amount + 1, amount + 1); | ||
| for (int a = 1; a <= amount; a++) { | ||
| for (int c : coins) { | ||
| if (c <= a) { | ||
| dp[a] = Math.min(dp[a], 1 + dp[a - c]); | ||
| } | ||
| } | ||
| } | ||
| if (dp[amount] > amount) { | ||
| return -1; | ||
| } | ||
| return dp[amount]; | ||
| } |
There was a problem hiding this comment.
🛠️ Refactor suggestion | 🟠 Major
Add required Javadoc with Time and Space Complexity tags.
Both SolutionDp and the broader package are missing the required HTML-formatted Javadoc block. Per the coding guidelines, every Solution*.java must document Time and Space Complexity.
📝 Proposed Javadoc addition
+/**
+ * Bottom-up DP using {`@code` amount + 1} as the infinity sentinel.
+ *
+ * <p><b>Time Complexity:</b> O(amount × coins.length)
+ *
+ * <p><b>Space Complexity:</b> O(amount)
+ */
class SolutionDp {As per coding guidelines, src/main/java/codes/yam/leetcode/**/Solution*.java: "Solution classes must be package-scoped (not public), use prefix naming (Solution, SolutionNaive, SolutionDp, etc.), and include HTML-formatted Javadoc with Time Complexity and Space Complexity tags."
📝 Committable suggestion
‼️ IMPORTANT
Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation. Thoroughly test & benchmark the code to ensure it meets the requirements.
| class SolutionDp { | |
| int coinChange(int[] coins, int amount) { | |
| int[] dp = new int[amount + 1]; | |
| Arrays.fill(dp, 1, amount + 1, amount + 1); | |
| for (int a = 1; a <= amount; a++) { | |
| for (int c : coins) { | |
| if (c <= a) { | |
| dp[a] = Math.min(dp[a], 1 + dp[a - c]); | |
| } | |
| } | |
| } | |
| if (dp[amount] > amount) { | |
| return -1; | |
| } | |
| return dp[amount]; | |
| } | |
| /** | |
| * Bottom-up DP using {`@code` amount + 1} as the infinity sentinel. | |
| * | |
| * <p><b>Time Complexity:</b> O(amount × coins.length) | |
| * | |
| * <p><b>Space Complexity:</b> O(amount) | |
| */ | |
| class SolutionDp { | |
| int coinChange(int[] coins, int amount) { | |
| int[] dp = new int[amount + 1]; | |
| Arrays.fill(dp, 1, amount + 1, amount + 1); | |
| for (int a = 1; a <= amount; a++) { | |
| for (int c : coins) { | |
| if (c <= a) { | |
| dp[a] = Math.min(dp[a], 1 + dp[a - c]); | |
| } | |
| } | |
| } | |
| if (dp[amount] > amount) { | |
| return -1; | |
| } | |
| return dp[amount]; | |
| } | |
| } |
🤖 Prompt for AI Agents
Verify each finding against the current code and only fix it if needed.
In `@src/main/java/codes/yam/leetcode/coinchange/SolutionDp.java` around lines 5 -
20, Add an HTML-formatted Javadoc block immediately above the class declaration
for SolutionDp describing the class and include explicit `@Time` Complexity and
`@Space` Complexity tags (e.g., "Time Complexity: O(amount * coins.length)" and
"Space Complexity: O(amount)") documenting the coinChange(int[] coins, int
amount) DP solution; ensure the Javadoc uses standard HTML tags and adheres to
the package-scoped Solution*.java guidelines.
| @@ -0,0 +1,26 @@ | |||
| package codes.yam.leetcode.coinchange; | |||
|
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| class SolutionDpNaive { | |||
There was a problem hiding this comment.
🛠️ Refactor suggestion | 🟠 Major
Add required Javadoc with Time and Space Complexity tags.
Same guideline violation as SolutionDp.java.
📝 Proposed Javadoc addition
+/**
+ * Bottom-up DP using {`@code` -1} as the sentinel for unreachable states.
+ *
+ * <p><b>Time Complexity:</b> O(amount × coins.length)
+ *
+ * <p><b>Space Complexity:</b> O(amount)
+ */
class SolutionDpNaive {As per coding guidelines, src/main/java/codes/yam/leetcode/**/Solution*.java: "Solution classes must be package-scoped (not public), use prefix naming (Solution, SolutionNaive, SolutionDp, etc.), and include HTML-formatted Javadoc with Time Complexity and Space Complexity tags."
📝 Committable suggestion
‼️ IMPORTANT
Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation. Thoroughly test & benchmark the code to ensure it meets the requirements.
| class SolutionDpNaive { | |
| /** | |
| * Bottom-up DP using {`@code` -1} as the sentinel for unreachable states. | |
| * | |
| * <p><b>Time Complexity:</b> O(amount × coins.length) | |
| * | |
| * <p><b>Space Complexity:</b> O(amount) | |
| */ | |
| class SolutionDpNaive { |
🤖 Prompt for AI Agents
Verify each finding against the current code and only fix it if needed.
In `@src/main/java/codes/yam/leetcode/coinchange/SolutionDpNaive.java` at line 3,
Add an HTML-formatted Javadoc block immediately above the class declaration for
SolutionDpNaive that documents the algorithm and includes explicit "Time
Complexity" and "Space Complexity" lines (e.g., using <p> or <b> tags to label
them) so the class follows the project guideline for Solution* classes; keep the
class package-scoped and retain the existing class name SolutionDpNaive while
filling in the accurate Big-O complexities for the implemented DP naive coin
change approach.
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Summary by CodeRabbit
Release Notes
New Features
Tests
Documentation