Add PrefixToInfix.java new algorithm (#5552)

* Add `PrefixToInfix.java` new algorithm

* Update directory

* Fix clang error

* Update directory

* Fix comment

* Add suggested changes

---------

Co-authored-by: Hardvan <Hardvan@users.noreply.github.com>
Co-authored-by: Alex Klymenko <alexanderklmn@gmail.com>

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

@@ -0,0 +1,44 @@
+package com.thealgorithms.stacks;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import java.util.stream.Stream;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+class PrefixToInfixTest {
+
+    @ParameterizedTest
+    @MethodSource("provideValidPrefixToInfixTestCases")
+    void testValidPrefixToInfixConversion(String prefix, String expectedInfix) {
+        assertEquals(expectedInfix, PrefixToInfix.getPrefixToInfix(prefix));
+    }
+
+    static Stream<Arguments> provideValidPrefixToInfixTestCases() {
+        return Stream.of(Arguments.of("A", "A"), // Single operand
+            Arguments.of("+AB", "(A+B)"), // Addition
+            Arguments.of("*+ABC", "((A+B)*C)"), // Addition and multiplication
+            Arguments.of("-+A*BCD", "((A+(B*C))-D)"), // Mixed operators
+            Arguments.of("/-A*BC+DE", "((A-(B*C))/(D+E))"), // Mixed operators
+            Arguments.of("^+AB*CD", "((A+B)^(C*D))") // Mixed operators
+        );
+    }
+
+    @Test
+    void testEmptyPrefixExpression() {
+        assertEquals("", PrefixToInfix.getPrefixToInfix(""));
+    }
+
+    @Test
+    void testNullPrefixExpression() {
+        assertThrows(NullPointerException.class, () -> PrefixToInfix.getPrefixToInfix(null));
+    }
+
+    @Test
+    void testMalformedPrefixExpression() {
+        assertThrows(ArithmeticException.class, () -> PrefixToInfix.getPrefixToInfix("+ABC"));
+    }
+}