Support gradle build.

Author: Jinge Wang

.gitattributes

@@ -0,0 +1,6 @@
+#
+# https://help.github.com/articles/dealing-with-line-endings/
+#
+# These are explicitly windows files and should use crlf
+*.bat           text eol=crlf
+

.gitignore

@@ -1,4 +1,9 @@
 # Default ignored files
 /.idea/shelf/
 /.idea/workspace.xml
-/out/
+/out/
+# Ignore Gradle project-specific cache directory
+.gradle
+
+# Ignore Gradle build output directory
+build

.idea/compiler.xml

@@ -1,28 +1,13 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<module type="JAVA_MODULE" version="4">
+<module external.linked.project.id="Algorithms" external.linked.project.path="$MODULE_DIR$" external.root.project.path="$MODULE_DIR$" external.system.id="GRADLE" external.system.module.group="" external.system.module.version="unspecified" type="JAVA_MODULE" version="4">
   <component name="NewModuleRootManager" inherit-compiler-output="true">
     <exclude-output />
     <content url="file://$MODULE_DIR$">
-      <sourceFolder url="file://$MODULE_DIR$/src" isTestSource="false" />
-      <sourceFolder url="file://$MODULE_DIR$/test" isTestSource="true" />
+      <excludeFolder url="file://$MODULE_DIR$/.gradle" />
+      <excludeFolder url="file://$MODULE_DIR$/build" />
+      <excludeFolder url="file://$MODULE_DIR$/out" />
     </content>
     <orderEntry type="inheritedJdk" />
     <orderEntry type="sourceFolder" forTests="false" />
-    <orderEntry type="module-library" scope="TEST">
-      <library name="JUnit5.8.1">
-        <CLASSES>
-          <root url="jar://$MAVEN_REPOSITORY$/org/junit/jupiter/junit-jupiter/5.8.1/junit-jupiter-5.8.1.jar!/" />
-          <root url="jar://$MAVEN_REPOSITORY$/org/junit/jupiter/junit-jupiter-api/5.8.1/junit-jupiter-api-5.8.1.jar!/" />
-          <root url="jar://$MAVEN_REPOSITORY$/org/opentest4j/opentest4j/1.2.0/opentest4j-1.2.0.jar!/" />
-          <root url="jar://$MAVEN_REPOSITORY$/org/junit/platform/junit-platform-commons/1.8.1/junit-platform-commons-1.8.1.jar!/" />
-          <root url="jar://$MAVEN_REPOSITORY$/org/apiguardian/apiguardian-api/1.1.2/apiguardian-api-1.1.2.jar!/" />
-          <root url="jar://$MAVEN_REPOSITORY$/org/junit/jupiter/junit-jupiter-params/5.8.1/junit-jupiter-params-5.8.1.jar!/" />
-          <root url="jar://$MAVEN_REPOSITORY$/org/junit/jupiter/junit-jupiter-engine/5.8.1/junit-jupiter-engine-5.8.1.jar!/" />
-          <root url="jar://$MAVEN_REPOSITORY$/org/junit/platform/junit-platform-engine/1.8.1/junit-platform-engine-1.8.1.jar!/" />
-        </CLASSES>
-        <JAVADOC />
-        <SOURCES />
-      </library>
-    </orderEntry>
   </component>
 </module>