diff --git a/.idea/.gitignore b/.idea/.gitignore
new file mode 100644
index 0000000..3575a72
--- /dev/null
+++ b/.idea/.gitignore
@@ -0,0 +1,10 @@
+# Default ignored files
+/shelf/
+/workspace.xml
+# Editor-based HTTP Client requests
+/httpRequests/
+# Ignored default folder with query files
+/queries/
+# Datasource local storage ignored files
+/dataSources/
+/dataSources.local.xml
diff --git a/.idea/gradle.xml b/.idea/gradle.xml
new file mode 100644
index 0000000..167d83b
--- /dev/null
+++ b/.idea/gradle.xml
@@ -0,0 +1,16 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="GradleSettings">
+    <option name="linkedExternalProjectsSettings">
+      <GradleProjectSettings>
+        <option name="externalProjectPath" value="$PROJECT_DIR$" />
+        <option name="gradleJvm" value="#JAVA_HOME" />
+        <option name="modules">
+          <set>
+            <option value="$PROJECT_DIR$" />
+          </set>
+        </option>
+      </GradleProjectSettings>
+    </option>
+  </component>
+</project>
\ No newline at end of file
diff --git a/.idea/kotlinc.xml b/.idea/kotlinc.xml
new file mode 100644
index 0000000..48de0f4
--- /dev/null
+++ b/.idea/kotlinc.xml
@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="KotlinJpsPluginSettings">
+    <option name="externalSystemId" value="Gradle" />
+    <option name="version" value="1.8.0" />
+  </component>
+</project>
\ No newline at end of file
diff --git a/.idea/misc.xml b/.idea/misc.xml
new file mode 100644
index 0000000..6b39356
--- /dev/null
+++ b/.idea/misc.xml
@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="ExternalStorageConfigurationManager" enabled="true" />
+  <component name="KubernetesApiProvider"><![CDATA[{}]]></component>
+  <component name="ProjectRootManager" version="2" languageLevel="JDK_11" project-jdk-name="11" project-jdk-type="JavaSDK" />
+</project>
\ No newline at end of file
diff --git a/.idea/vcs.xml b/.idea/vcs.xml
new file mode 100644
index 0000000..c8397c9
--- /dev/null
+++ b/.idea/vcs.xml
@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="VcsDirectoryMappings">
+    <mapping directory="" vcs="Git" />
+  </component>
+</project>
\ No newline at end of file
diff --git a/src/main/kotlin/mate/academy/ProcessAndFilterNumbers.kt b/src/main/kotlin/mate/academy/ProcessAndFilterNumbers.kt
index 20d40f2..ca3fa68 100644
--- a/src/main/kotlin/mate/academy/ProcessAndFilterNumbers.kt
+++ b/src/main/kotlin/mate/academy/ProcessAndFilterNumbers.kt
@@ -1,5 +1,15 @@
 package mate.academy
 
-fun processAndFilterNumbers(numbers: List<Int>): List<Int> {
+/**
+ * Transform each number: if even -> half, if odd -> doubled, then return only values > 25.
+ * Implemented using a Sequence to avoid creating intermediate lists for large inputs.
+ */
+const val THRESHOLD = 25
+const val EVEN_DIVISOR = 2
+const val ODD_MULTIPLIER = 2
+fun processAndFilterNumbers(numbers: List<Int>): List<Int> =
+    numbers.asSequence()
+        .map { if (it % 2 == 0) it / EVEN_DIVISOR else it * ODD_MULTIPLIER }
+        .filter { it > THRESHOLD }
+        .toList()
 
-}