Added reverse array solution

Author: viktor-podzigun

.gitignore

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+*.class
+*.log
+
+# sbt specific
+.cache
+.history
+.lib/
+.idea/
+dist/*
+target/
+build/
+node_modules/
+lib_managed/
+src_managed/
+project/boot/
+project/plugins/project/
+
+# Scala-IDE specific
+.scala_dependencies
+.worksheet

.travis.yml

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+language: scala
+jdk:
+- oraclejdk8
+dist: trusty
+env:
+  global:
+  - TRAVIS_SBT_VERSION="1.2.8"
+script:
+- sbt test
+cache:
+  directories:
+  - "$HOME/.ivy2/cache"
+  - "$HOME/.sbt"
+before_cache:
+# Cleanup the cached directories to avoid unnecessary cache updates
+- find $HOME/.ivy2/cache -name "ivydata-*.properties" -print -delete
+- find $HOME/.sbt        -name "*.lock"               -print -delete

README.md

@@ -1,2 +1,17 @@
-# data-algorithms
+
+[![Build Status](https://travis-ci.org/viktor-podzigun/data-algorithms.svg?branch=master)](https://travis-ci.org/viktor-podzigun/data-algorithms)
+
+## data-algorithms
 My solutions to different data structures and algorithms problems
+
+### How to build/run it
+
+To build and run all tests use the following command:
+```bash
+sbt test
+```
+
+### Overview
+
+* Arrays
+  * [ReverseArray](src/main/java/algorithms/array/ReverseArray.java) => [test](src/test/scala/algorithms/array/ReverseArraySpec.scala)

build.sbt

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+
+val ideExcludedDirectories = SettingKey[Seq[File]]("ide-excluded-directories")
+
+lazy val `elevator-challenge` = (project in file("."))
+  .settings(
+    organization := "org.scommons.viktor-podzigun",
+    name := "data-algorithms",
+    description := "My solutions to different data structures and algorithms problems",
+    scalaVersion := "2.12.10",
+    scalacOptions ++= Seq(
+      //see https://docs.scala-lang.org/overviews/compiler-options/index.html#Warning_Settings
+      //"-Xcheckinit",
+      "-Xfatal-warnings",
+      "-Xlint:_",
+      "-Ywarn-macros:after", // Only inspect expanded trees when generating unused symbol warnings
+      "-explaintypes",
+      "-unchecked",
+      "-deprecation",
+      "-feature"
+    ),
+    
+    ideExcludedDirectories := {
+      val base = baseDirectory.value
+      List(
+        base / ".idea",
+        base / "target"
+      )
+    },
+    
+    libraryDependencies ++= Seq(
+      "org.scalatest" %% "scalatest" % "3.0.1" % "test"
+    ),
+
+    //when run tests with coverage: "sbt clean coverage test coverageReport"
+    coverageMinimum := 80
+  )

project/build.properties

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+sbt.version=1.2.8

project/plugins.sbt

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+
+addSbtPlugin("org.scoverage" % "sbt-scoverage" % "1.5.1")
+addSbtPlugin("org.scoverage" % "sbt-coveralls" % "1.2.4")

src/main/java/algorithms/array/ReverseArray.java

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+package algorithms.array;
+
+public class ReverseArray {
+    
+    public static int[] reverse(int[] arr) {
+        for (int i = 0, j = arr.length - 1; i < j; i++, j--) {
+            int tmp = arr[i];
+            arr[i] = arr[j];
+            arr[j] = tmp;
+
+            //printArray(arr);
+        }
+        
+        return arr;
+    }
+    
+     static void printArray(int[] arr) {
+        StringBuilder sb = new StringBuilder("[");
+        for (int i = 0; i < arr.length; i++) {
+            if (i > 0) {
+                sb.append(", ");
+            }
+            
+            sb.append(arr[i]);
+        }
+
+        sb.append("]");
+        System.out.println(sb.toString());
+    }
+}

src/test/scala/algorithms/array/ReverseArraySpec.scala

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+package algorithms.array
+
+import org.scalatest.{FlatSpec, Matchers}
+
+class ReverseArraySpec extends FlatSpec with Matchers {
+
+  it should "reverse the whole array" in {
+    //given
+    val arr = Array(1, 2, 3, 4, 5)
+    
+    //when
+    val result = ReverseArray.reverse(arr)
+    
+    //then
+    result.toList shouldBe List(5, 4, 3, 2, 1)
+  }
+}