solves two sum

Author: anishLearnsToCode

.gitignore

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+.idea
+out

CONTRIBUTING.md

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+# Contributing Guidelines
+
+This project aims to create a common source from all algorithms questions on HackerRank and values every single 
+contribution made by the community.
+
+We aim to solve all questions in the HackerRank Algorithms  domain in as many languages as possible to show the 
+different code styles and approaches that can be used to solve the same problem.
+ 
+Contributing is very simple, simply identify a question from the [README](README.md) file that has yet to be solved in
+a programming language of your choice. 
+
+Solve that question and make sure that all tests pass on HackerRank and then create a pull request with the 
+added solution and updated readme.
+  
+## Pull Request Process
+
+1. Fork this repository to your github account and then clone your forked repository to your machine.
+2. Say you solve some problem called __cars-and-trucks__ in the _Implementation_ sub domain on 
+    HackerRank using your favorite programming language, say Python then simple add a new file called 
+    `cars-and-trucks.py` in the `implimentation` directory. 
+3. In the [README](README.md) file, add a Python logo along with an empty link.
+4. Updating the link for the solution will be done by the Project maintainers (aka. [anishLearnsToCode]())
+
+## Programming Language Logos
+To add a logo in the [README](README.md) table simply add a link with an embedded picture as 
+```markdown
+[![Python](icon-link)](this link will be filled by the author if the pull request is accepted)
+```
+
+For the icon link refer to the table below to obtain the link for a specific programming language:
+
+| Programming Language | Icon | Icon Link|
+|:--------------------:|:----:|:----:|
+| Java | ![Java](https://img.icons8.com/color/40/000000/java-coffee-cup-logo.png) | https://img.icons8.com/color/40/000000/java-coffee-cup-logo.png |
+| Python | ![Python](https://img.icons8.com/color/35/000000/python.png) | https://img.icons8.com/color/35/000000/python.png |
+| C | ![C](https://img.icons8.com/color/35/000000/c-programming.png) | https://img.icons8.com/color/35/000000/c-programming.png |
+| C++ | ![C++](https://img.icons8.com/color/35/000000/c-plus-plus-logo.png) | https://img.icons8.com/color/35/000000/c-plus-plus-logo.png |
+| C# | ![C#](https://img.icons8.com/color/35/000000/c-sharp-logo.png) | https://img.icons8.com/color/35/000000/c-sharp-logo.png |
+| JavaScript | ![JavaScript](https://img.icons8.com/color/40/000000/javascript.png) | https://img.icons8.com/color/40/000000/javascript.png |
+| TypeScript | ![TypeScript](https://img.icons8.com/color/40/000000/typescript.png) | https://img.icons8.com/color/40/000000/typescript.png |
+| Ruby | ![Ruby](https://img.icons8.com/office/35/000000/ruby-programming-language.png) | https://img.icons8.com/office/35/000000/ruby-programming-language.png |
+| Scala | ![Scala](https://img.icons8.com/dusk/35/000000/scala.png) | https://img.icons8.com/office/35/000000/ruby-programming-language.png |
+| PGH | ![PHP](https://img.icons8.com/officel/40/000000/php-logo.png) | https://img.icons8.com/officel/40/000000/php-logo.png |
+| Swift | ![Swift](https://img.icons8.com/fluent/40/000000/swift.png) | https://img.icons8.com/fluent/40/000000/swift.png |
+
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+

README.md

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+# Leetcode Algorithms
+
+## Problems
+| # Number | Name | Difficulty | Solution |
+|:--------:|------|:----------:|:--------:|
+| 1 | [Two Sum](https://leetcode.com/problems/two-sum/) | Easy | | 

leetcode-algorithms.iml

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+<?xml version="1.0" encoding="UTF-8"?>
+<module 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" />
+    </content>
+    <orderEntry type="inheritedJdk" />
+    <orderEntry type="sourceFolder" forTests="false" />
+  </component>
+</module>

src/TwoSum.java

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+// https://leetcode.com/problems/two-sum/
+
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Scanner;
+
+public class TwoSum {
+    private static final Scanner scanner = new Scanner(System.in);
+
+    public static void main(String[] args) {
+        int length = scanner.nextInt();
+        int[] array = getArray(length);
+        int target = scanner.nextInt();
+        System.out.println(Arrays.toString(twoSum(array, target)));
+    }
+
+    private static int[] getArray(int length) {
+        int[] array = new int[length];
+        for (int index = 0 ; index < array.length ; index++) {
+            array[index] = scanner.nextInt();
+        }
+        return array;
+    }
+
+    public static int[] twoSum(int[] array, int target) {
+        Map<Integer, Integer> indices = getIndices(array);
+        for (int index = 0 ; index < array.length ; index++) {
+            int number = array[index];
+            if (indices.containsKey(target - number) && indices.get(target - number) != index) {
+                return new int[] {index, indices.get(target - number)};
+            }
+        }
+        return new int[0];
+    }
+
+    private static Map<Integer, Integer> getIndices(int[] array) {
+        Map<Integer, Integer> indices = new HashMap<>();
+        for (int index = 0 ; index < array.length ; index++) {
+            indices.put(array[index], index);
+        }
+        return indices;
+    }
+}