Implement findings from static code analysis

Author: spannm

src/main/java/io/github/spannm/leetcode/dep/Sudoku.java

@@ -467,17 +467,17 @@ public boolean equals(Object _obj) {
                 return false;
             }
             Field other = (Field) _obj;
-            boolean equals = java.util.Objects.equals(value, other.value);
+            boolean equals = Objects.equals(value, other.value);
             if (equals) {
-                equals = java.util.Objects.equals(areas.values().stream().map(Area::getItemNo).toList(),
+                equals = Objects.equals(areas.values().stream().map(Area::getItemNo).toList(),
                     other.areas.values().stream().map(Area::getItemNo).toList());
             }
             return equals;
         }
 
         @Override
         public int hashCode() {
-            return java.util.Objects.hash(value, areas);
+            return Objects.hash(value, areas);
         }
 
         @Override

src/main/java/io/github/spannm/leetcode/lc0/lc0000/Problem0015.java

@@ -39,7 +39,7 @@ List<List<Integer>> threeSum2(int[] _nums) {
     }
 
     public List<List<Integer>> threeSum(int[] _nums) {
-        List<Integer> input = java.util.Arrays.stream(_nums).sorted().boxed().toList();
+        List<Integer> input = Arrays.stream(_nums).sorted().boxed().toList();
         final int len = input.size();
         if (len < 3) {
             return List.of();

src/main/java/io/github/spannm/leetcode/lc0/lc0000/Problem0081.java

@@ -16,10 +16,8 @@ boolean search(int[] _nums, int _target) {
                 break;
             }
         }
-        if (binSearch(_nums, 0, pivot, _target) >= 0) {
-            return true;
-        }
-        return binSearch(_nums, pivot + 1, len - 1, _target) > 0;
+        return binSearch(_nums, 0, pivot, _target) >= 0
+            || binSearch(_nums, pivot + 1, len - 1, _target) > 0;
     }
 
     static int binSearch(int[] _nums, int _l, int _r, int _target) {

src/main/java/io/github/spannm/leetcode/lc0/lc0200/Problem0211.java

@@ -46,10 +46,7 @@ static boolean search(TrieNode _node, String _word, int _index) {
                 return false;
             } else {
                 TrieNode child = _node.children.get(c);
-                if (child == null) {
-                    return false;
-                }
-                return search(child, _word, _index + 1);
+                return child != null && search(child, _word, _index + 1);
             }
         }
 

src/main/java/io/github/spannm/leetcode/lc0/lc0200/Problem0230.java

@@ -14,16 +14,13 @@ int kthSmallest(TreeNode _root, int _k) {
         return inorder.get(_k - 1);
     }
 
-    private static void dfs(TreeNode _root, List<Integer> _list, int _k) {
+    static void dfs(TreeNode _root, List<Integer> _list, int _k) {
         if (_root == null) {
             return;
         }
         dfs(_root.left, _list, _k);
         _list.add(_root.val);
         dfs(_root.right, _list, _k);
-        if (_list.size() >= _k - 1) {
-            return;
-        }
     }
 
 }

src/main/java/io/github/spannm/leetcode/lc0/lc0200/Problem0291.java

@@ -24,11 +24,7 @@ static boolean isMatch(String _str, int _i, String _pattern, int _j, Map<Charact
 
         if (_map.containsKey(c)) {
             String s = _map.get(c);
-
-            if (!_str.startsWith(s, _i)) {
-                return false;
-            }
-            return isMatch(_str, _i + s.length(), _pattern, _j + 1, _map, _set);
+            return _str.startsWith(s, _i) && isMatch(_str, _i + s.length(), _pattern, _j + 1, _map, _set);
         }
 
         for (int k = _i; k < _str.length(); k++) {

src/main/java/io/github/spannm/leetcode/lc0/lc0400/Problem0479.java

@@ -11,7 +11,7 @@ int largestPalindrome(int _n) {
 
         int upperBound = (int) Math.pow(10, _n) - 1;
         int lowerBound = upperBound / 10;
-        long maxNumber = (long) upperBound * (long) upperBound;
+        long maxNumber = upperBound * (long) upperBound;
 
         int firstHalf = (int) (maxNumber / (long) Math.pow(10, _n));
 

src/main/java/io/github/spannm/leetcode/lc0/lc0400/Problem0480.java

@@ -49,7 +49,7 @@ public void addNum(int _num) {
         }
 
         public double findMedian() {
-            return (k & 1) == 1 ? small.peek() : ((double) small.peek() + large.peek()) / 2;
+            return (k & 1) == 1 ? small.peek() : (small.peek() + large.peek()) / 2D;
         }
 
         public void removeNum(int _num) {

src/main/java/io/github/spannm/leetcode/lc0/lc0500/Problem0501.java

@@ -20,8 +20,8 @@ static List<Integer> bfs(TreeNode _root, Map<Integer, Integer> _map) {
             int size = queue.size();
             for (int i = 0; i < size; i++) {
                 TreeNode tn = queue.poll();
-                java.util.Optional.ofNullable(tn.left).ifPresent(queue::offer);
-                java.util.Optional.ofNullable(tn.right).ifPresent(queue::offer);
+                Optional.ofNullable(tn.left).ifPresent(queue::offer);
+                Optional.ofNullable(tn.right).ifPresent(queue::offer);
                 _map.compute(tn.val, (k, v) -> v == null ? 1 : v + 1);
             }
         }

src/main/java/io/github/spannm/leetcode/lc0/lc0700/Problem0794.java

@@ -7,43 +7,36 @@
  */
 class Problem0794 extends LeetcodeProblem {
 
-    private String[] board;
-
-    public boolean validTicTacToe(String[] _board) {
-        board = _board;
-        int x = count('X');
-        int o = count('O');
-        if (x != o && x - 1 != o || win('X') && x - 1 != o) {
+    boolean validTicTacToe(String[] _board) {
+        int x = count(_board, 'X');
+        int o = count(_board, 'O');
+        if (x != o && x - 1 != o || win(_board, 'X') && x - 1 != o) {
             return false;
         }
-        return !(win('O') && x != o);
+        return !(win(_board, 'O') && x != o);
     }
 
-    private boolean win(char _x) {
+    static boolean win(String[] _board, char _x) {
         for (int i = 0; i < 3; i++) {
-            if (board[i].charAt(0) == _x && board[i].charAt(1) == _x && board[i].charAt(2) == _x) {
-                return true;
-            }
-            if (board[0].charAt(i) == _x && board[1].charAt(i) == _x && board[2].charAt(i) == _x) {
+            if ((_board[i].charAt(0) == _x && _board[i].charAt(1) == _x && _board[i].charAt(2) == _x)
+             || (_board[0].charAt(i) == _x && _board[1].charAt(i) == _x && _board[2].charAt(i) == _x)) {
                 return true;
             }
         }
-        if (board[0].charAt(0) == _x && board[1].charAt(1) == _x && board[2].charAt(2) == _x) {
-            return true;
-        }
-        return board[0].charAt(2) == _x && board[1].charAt(1) == _x && board[2].charAt(0) == _x;
+        return (_board[0].charAt(0) == _x && _board[1].charAt(1) == _x && _board[2].charAt(2) == _x)
+            || (_board[0].charAt(2) == _x && _board[1].charAt(1) == _x && _board[2].charAt(0) == _x);
     }
 
-    private int count(char _x) {
-        int cnt = 0;
-        for (var row : board) {
-            for (var c : row.toCharArray()) {
+    static int count(String[] _board, char _x) {
+        int count = 0;
+        for (String row : _board) {
+            for (char c : row.toCharArray()) {
                 if (c == _x) {
-                    cnt++;
+                    count++;
                 }
             }
         }
-        return cnt;
+        return count;
     }
 
 }

src/main/java/io/github/spannm/leetcode/lc0/lc0800/Problem0863.java

@@ -22,12 +22,12 @@ List<Integer> distanceK(final TreeNode _root, final TreeNode _target, int _k) {
             for (int i = 0; i < size; i++) {
                 TreeNode top = q.poll();
 
-                java.util.Optional.ofNullable(top.left).ifPresent(n -> {
+                Optional.ofNullable(top.left).ifPresent(n -> {
                     parent.put(n.val, top);
                     q.offer(n);
                 });
 
-                java.util.Optional.ofNullable(top.right).ifPresent(n -> {
+                Optional.ofNullable(top.right).ifPresent(n -> {
                     parent.put(n.val, top);
                     q.offer(n);
                 });

src/main/java/io/github/spannm/leetcode/lc0/lc0900/Problem0966.java

@@ -14,9 +14,7 @@ String[] spellchecker(String[] _wordlist, String[] _queries) {
         Set<String> set = new HashSet<>();
 
         for (String word : _wordlist) {
-            if (!caseMap.containsKey(word.toLowerCase())) {
-                caseMap.put(word.toLowerCase(), word);
-            }
+            caseMap.putIfAbsent(word.toLowerCase(), word);
             set.add(word);
         }
 

src/main/java/io/github/spannm/leetcode/lc1/lc1100/Problem1114.java

@@ -67,32 +67,29 @@ private synchronized void doAction(int _order, Runnable _r) throws InterruptedEx
 
     }
 
+    @SuppressWarnings("PMD.EmptyCatchBlock")
     public static void main(String[] _args) throws InterruptedException {
         Foo foo = new Foo(2, 1, 3);
         List<Thread> threads = new ArrayList<>(List.of(
             new Thread(() -> {
                 try {
                     foo.first(foo::first);
                 } catch (InterruptedException _ex) {
-                    return;
                 }
             }, "t1"),
             new Thread(() -> {
                 try {
                     foo.second(foo::second);
                 } catch (InterruptedException _ex) {
-                    return;
                 }
             }, "t2"),
             new Thread(() -> {
                 try {
                     foo.third(foo::third);
                 } catch (InterruptedException _ex) {
-                    return;
                 }
             }, "t3")));
         Collections.shuffle(threads);
-        // threads.forEach(t -> t.setDaemon(false));
         threads.forEach(Thread::start);
 
         Thread.sleep(500L);

src/main/java/io/github/spannm/leetcode/lc1/lc1100/Problem1115.java

@@ -45,20 +45,19 @@ public void bar(Runnable _printBar) throws InterruptedException {
             }
         }
 
+        @SuppressWarnings("PMD.EmptyCatchBlock")
         public static void main(String[] _args) {
             FooBar fooBar = new FooBar(1);
             Thread ft = new Thread(() -> {
                 try {
                     fooBar.foo(() -> System.out.print("foo"));
                 } catch (InterruptedException _ex) {
-                    return;
                 }
             }, "fooThread");
             Thread bt = new Thread(() -> {
                 try {
                     fooBar.bar(() -> System.out.print("bar"));
                 } catch (InterruptedException _ex) {
-                    return;
                 }
             }, "barThread");
             ft.start();

src/main/java/io/github/spannm/leetcode/lc1/lc1100/Problem1117.java

@@ -8,6 +8,7 @@
 /**
  * <a href="https://leetcode.com/problems/building-h2o/">1117. Building H2O</a>.
  */
+@SuppressWarnings("PMD.EmptyCatchBlock")
 class Problem1117 extends LeetcodeProblem {
 
     private final CyclicBarrier barrier = new CyclicBarrier(3);
@@ -21,7 +22,6 @@ public void hydrogen(Runnable _releaseHydrogen) {
             // releaseHydrogen.run() outputs "H". Do not change or remove this line.
             _releaseHydrogen.run();
         } catch (Exception _ex) {
-            return;
         } finally {
             hSem.release();
         }
@@ -35,7 +35,6 @@ public void oxygen(Runnable _releaseOxygen) {
             // releaseOxygen.run() outputs "O". Do not change or remove this line.
             _releaseOxygen.run();
         } catch (Exception _ex) {
-            return;
         } finally {
             oSem.release();
         }

src/main/java/io/github/spannm/leetcode/lc1/lc1200/Problem1258.java

@@ -47,10 +47,7 @@ private String formWord(String[] _words) {
     private Map<String, Set<String>> buildSynonymDict(String[] _words, List<List<String>> _synonyms) {
         Map<String, Set<String>> map = new HashMap<>();
         for (String key : _words) {
-            if (!map.containsKey(key)) {
-                map.put(key, new HashSet<>());
-            }
-            map.get(key).add(key);
+            map.computeIfAbsent(key, k -> new HashSet<>()).add(key);
         }
         for (List<String> list : _synonyms) {
             for (String key : map.keySet()) {

src/main/java/io/github/spannm/leetcode/lc1/lc1200/Problem1286.java

@@ -24,7 +24,6 @@ static class CombinationIterator {
         private void buildAllCombinations(String _characters, int _start, StringBuilder _sb, boolean[] _visited) {
             if (_sb.length() == combinationLength) {
                 list.add(_sb.toString());
-                return;
             } else {
                 for (int i = _start; i < _characters.length();) {
                     if (!_visited[i]) {

src/main/java/io/github/spannm/leetcode/lc1/lc1300/Problem1344.java

@@ -7,7 +7,7 @@ class Problem1344 extends LeetcodeProblem {
     double angleClock(int _hour, int _minutes) {
         double minAngle = _minutes * 360 / 60;
         double hourAnglePart1 = _hour != 12 ? _hour * 360 / 12 : 0;
-        double hourAnglePart2 = (double) (30 * _minutes) / (double) 60;
+        double hourAnglePart2 = (30 * _minutes) / 60D;
         double hourAngle = hourAnglePart1 + hourAnglePart2;
         double preResult = Math.abs(minAngle - hourAngle);
         return preResult > 180 ? 360 - preResult : preResult;

src/main/java/io/github/spannm/leetcode/lc1/lc1300/Problem1381.java

@@ -8,7 +8,6 @@
 class Problem1381 extends LeetcodeProblem {
 
     static class CustomStack {
-
         private final List<Integer> list;
         private final int           maxSize;
 
@@ -18,19 +17,13 @@ static class CustomStack {
         }
 
         void push(int _x) {
-            if (list.size() >= maxSize) {
-                return;
-            } else {
+            if (list.size() < maxSize) {
                 list.add(_x);
             }
         }
 
         int pop() {
-            if (!list.isEmpty()) {
-                return list.remove(list.size() - 1);
-            } else {
-                return -1;
-            }
+            return list.isEmpty() ? -1 : list.remove(list.size() - 1);
         }
 
         void increment(int _k, int _val) {

src/main/java/io/github/spannm/leetcode/lc1/lc1600/Problem1603.java

@@ -36,10 +36,7 @@ static class ParkingSystem2 {
         }
 
         public boolean addCar(int _carType) {
-            if (!slots.containsKey(_carType)) {
-                return false;
-            }
-            return slots.compute(_carType, (k, v) -> --v) > -1;
+            return slots.containsKey(_carType) && slots.compute(_carType, (k, v) -> --v) > -1;
         }
     }