style: use proper spelling

pmd-exclude.properties

@@ -12,7 +12,7 @@ com.thealgorithms.datastructures.crdt.LWWElementSet=UselessParentheses
 com.thealgorithms.datastructures.crdt.Pair=UnusedPrivateField
 com.thealgorithms.datastructures.graphs.AStar=UselessParentheses
 com.thealgorithms.datastructures.graphs.AdjacencyMatrixGraph=CollapsibleIfStatements,UnnecessaryFullyQualifiedName,UselessParentheses
-com.thealgorithms.datastructures.graphs.BipartiteGrapfDFS=CollapsibleIfStatements
+com.thealgorithms.datastructures.graphs.BipartiteGraphDFS=CollapsibleIfStatements
 com.thealgorithms.datastructures.graphs.Kruskal=UselessParentheses
 com.thealgorithms.datastructures.hashmap.hashing.HashMapCuckooHashing=UselessParentheses
 com.thealgorithms.datastructures.heaps.FibonacciHeap=UselessParentheses

src/main/java/com/thealgorithms/datastructures/graphs/BipartiteGrapfDFS.java → src/main/java/com/thealgorithms/datastructures/graphs/BipartiteGraphDFS.java

@@ -14,8 +14,8 @@
  *
  * Output : YES
  */
-public final class BipartiteGrapfDFS {
-    private BipartiteGrapfDFS() {
+public final class BipartiteGraphDFS {
+    private BipartiteGraphDFS() {
     }
 
     private static boolean bipartite(int v, ArrayList<ArrayList<Integer>> adj, int[] color, int node) {

src/main/java/com/thealgorithms/datastructures/lists/MergeKSortedLinkedlist.java → src/main/java/com/thealgorithms/datastructures/lists/MergeKSortedLinkedList.java

@@ -7,7 +7,7 @@
 /**
  * @author Arun Pandey (https://github.com/pandeyarun709)
  */
-public class MergeKSortedLinkedlist {
+public class MergeKSortedLinkedList {
 
     /**
      * This function merge K sorted LinkedList

src/main/java/com/thealgorithms/stacks/LargestRectangle.java

@@ -11,7 +11,7 @@ public final class LargestRectangle {
     private LargestRectangle() {
     }
 
-    public static String largestRectanglehistogram(int[] heights) {
+    public static String largestRectangleHistogram(int[] heights) {
         int n = heights.length;
         int maxArea = 0;
         Stack<int[]> st = new Stack<>();
@@ -32,7 +32,7 @@ public static String largestRectanglehistogram(int[] heights) {
     }
 
     public static void main(String[] args) {
-        assert largestRectanglehistogram(new int[] {2, 1, 5, 6, 2, 3}).equals("10");
-        assert largestRectanglehistogram(new int[] {2, 4}).equals("4");
+        assert largestRectangleHistogram(new int[] {2, 1, 5, 6, 2, 3}).equals("10");
+        assert largestRectangleHistogram(new int[] {2, 4}).equals("4");
     }
 }

src/main/java/com/thealgorithms/strings/ReverseWordsInString.java

@@ -13,7 +13,6 @@ private ReverseWordsInString() {
      * @param s the input string
      * @return A string created by reversing the order of the words in {@code s}
      */
-
     public static String reverseWordsInString(final String s) {
         var words = s.trim().split("\\s+");
         Collections.reverse(Arrays.asList(words));

src/main/java/com/thealgorithms/strings/Upper.java

@@ -15,13 +15,13 @@ public static void main(String[] args) {
     }
 
     /**
-     * Converts all of the characters in this {@code String} to upper case
+     * Converts all the characters in this {@code String} to upper case
      *
      * @param s the string to convert
      * @return the {@code String}, converted to uppercase.
      */
     public static String toUpperCase(String s) {
-        if (s == null || "".equals(s)) {
+        if (s == null || s.isEmpty()) {
             return s;
         }
         char[] values = s.toCharArray();

src/test/java/com/thealgorithms/stacks/LargestRectangleTest.java

@@ -11,19 +11,19 @@ void testLargestRectangleHistogramWithTypicalCases() {
         // Typical case with mixed heights
         int[] heights = {2, 1, 5, 6, 2, 3};
         String expected = "10";
-        String result = LargestRectangle.largestRectanglehistogram(heights);
+        String result = LargestRectangle.largestRectangleHistogram(heights);
         assertEquals(expected, result);
 
         // Another typical case with increasing heights
         heights = new int[] {2, 4};
         expected = "4";
-        result = LargestRectangle.largestRectanglehistogram(heights);
+        result = LargestRectangle.largestRectangleHistogram(heights);
         assertEquals(expected, result);
 
         // Case with multiple bars of the same height
         heights = new int[] {4, 4, 4, 4};
         expected = "16";
-        result = LargestRectangle.largestRectanglehistogram(heights);
+        result = LargestRectangle.largestRectangleHistogram(heights);
         assertEquals(expected, result);
     }
 
@@ -32,19 +32,19 @@ void testLargestRectangleHistogramWithEdgeCases() {
         // Edge case with an empty array
         int[] heights = {};
         String expected = "0";
-        String result = LargestRectangle.largestRectanglehistogram(heights);
+        String result = LargestRectangle.largestRectangleHistogram(heights);
         assertEquals(expected, result);
 
         // Edge case with a single bar
         heights = new int[] {5};
         expected = "5";
-        result = LargestRectangle.largestRectanglehistogram(heights);
+        result = LargestRectangle.largestRectangleHistogram(heights);
         assertEquals(expected, result);
 
         // Edge case with all bars of height 0
         heights = new int[] {0, 0, 0};
         expected = "0";
-        result = LargestRectangle.largestRectanglehistogram(heights);
+        result = LargestRectangle.largestRectangleHistogram(heights);
         assertEquals(expected, result);
     }
 
@@ -56,7 +56,7 @@ void testLargestRectangleHistogramWithLargeInput() {
             heights[i] = 1;
         }
         String expected = "10000";
-        String result = LargestRectangle.largestRectanglehistogram(heights);
+        String result = LargestRectangle.largestRectangleHistogram(heights);
         assertEquals(expected, result);
     }
 
@@ -65,13 +65,13 @@ void testLargestRectangleHistogramWithComplexCases() {
         // Complex case with a mix of heights
         int[] heights = {6, 2, 5, 4, 5, 1, 6};
         String expected = "12";
-        String result = LargestRectangle.largestRectanglehistogram(heights);
+        String result = LargestRectangle.largestRectangleHistogram(heights);
         assertEquals(expected, result);
 
         // Case with a peak in the middle
         heights = new int[] {2, 1, 5, 6, 2, 3, 1};
         expected = "10";
-        result = LargestRectangle.largestRectanglehistogram(heights);
+        result = LargestRectangle.largestRectangleHistogram(heights);
         assertEquals(expected, result);
     }
 }