refactor: improve Floor method to handle edge cases

src/main/java/com/thealgorithms/maths/Floor.java

@@ -1,24 +1,33 @@
 package com.thealgorithms.maths;
 
+/**
+ * Utility class to compute the floor of a given number.
+ */
 public final class Floor {
-
     private Floor() {
     }
 
     /**
-     * Returns the largest (closest to positive infinity)
+     * Returns the largest double value that is less than or equal to the input.
+     * Equivalent to mathematical ⌊x⌋ (floor function).
      *
-     * @param number the number
-     * @return the largest (closest to positive infinity) of given
-     * {@code number}
+     * @param number the number to floor
+     * @return the largest double less than or equal to {@code number}
      */
     public static double floor(double number) {
-        if (number - (int) number == 0) {
+        if (Double.isNaN(number) || Double.isInfinite(number) || number == 0.0 || number < Integer.MIN_VALUE || number > Integer.MAX_VALUE) {
             return number;
-        } else if (number - (int) number > 0) {
-            return (int) number;
+        }
+
+        if (number > 0.0 && number < 1.0) {
+            return 0.0;
+        }
+
+        long intPart = (long) number;
+        if (number < 0 && number != intPart) {
+            return intPart - 1.0;
         } else {
-            return (int) number - 1;
+            return intPart;
         }
     }
 }