Finished challenges

FindAllPairs.java

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+package com.company;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+
+public class FindAllPairs {
+  public static void findPairs(int[] testArray, int targetSum){
+    ArrayList<Integer> newArray = new ArrayList<Integer>();
+    //Array to store new sorted list without duplicates
+
+    Arrays.sort(testArray);
+    //Sorts test Array
+    //(1,2,4,4,5,5)
+
+    newArray.add(testArray[0]);
+    //Adds first element of testArray to the Arraylist
+
+    boolean targetSumHalf = false;
+    //boolean if exists a pair of numbers that are the same value, but added up equal targetSum
+
+    for (int i = 0; i < testArray.length-1; i ++){
+      //If there are a pair of duplicates (Pairs where both the numbers are the same, but their sums equal targetSum),
+      //they are counted as a pair.
+      if (newArray.get(newArray.size()-1)!=testArray[i+1]){
+        //Since list is expanding, checks previously added element with the testArray
+        newArray.add(testArray[i+1]);
+        //Adds testArray element if its unique to the recently added Arraylist element
+      }
+      else{
+        if (testArray[i+1]*2 == targetSum && targetSumHalf == false ){
+          System.out.println ("("+ newArray.get(newArray.size()-1)+","+ testArray[i+1]+")");
+          targetSumHalf = true;
+        }
+      }
+    }
+    //Now uses newArray, which has list with non-duplicate numbers
+    //(1,2,4,5)
+
+    //Starting at ends of the newArray
+    int start = 0;
+    int end = newArray.size()-1;
+
+    //Keeps on looping until the two ends have met.
+    while (start < end){
+      int sum = newArray.get(start) + newArray.get(end);
+
+      //checking if sum of the start and end index elements are equal to target sum
+      if (sum == targetSum){
+        //prints the pair, increments start and decrements end and continues
+        System.out.println ("("+ newArray.get(start)+","+ newArray.get(end)+")");
+        start++;
+        end--;
+      }
+      else if (sum < targetSum){
+        //if sum is less than targetSum, range moves up to use bigger numbers for comparison.
+        start++;
+      }
+      else{
+        // If sum is more than targetSum, range moves down to use smaller numbers.
+        end--;
+      }
+    }
+  }
+  public static void main(String[] args){
+    //Example values
+    int[] testArray = {2, 4, 5, 1, 3, 5, 4};
+    int targetSum = 6;
+
+    //Values to be printed on the console are
+    //(2,4)
+    //(1,5)
+    findPairs(testArray, targetSum);
+  }
+}

Palindrome.java

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+public class Palindrome{
+  public static boolean isPalindrome(String testString){
+    //starts at both ends of the word. Compares each letter and gets close to the middle letters.
+    //loop ends in the middle of the word.
+    //If its odd number of characters or word is one letter, middle letter is avoided.
+    for (int i = 0; i < testString.length()/2; i ++){
+      //If the two chars are not the same letter, return false
+      if (testString.charAt(i) != testString.charAt(testString.length()-i-1)){
+        return false;
+      }
+    }
+    //All letters of the word have been compared and resemble a palindrome
+    return true;
+  }
+  public static void main(String[] args) {
+    //Words that return true (Taken from question)
+    System.out.println(isPalindrome("radar"));
+    System.out.println(isPalindrome("bob"));
+    System.out.println(isPalindrome("asdfdsa"));
+
+    //Words that return false (I made these up)
+    System.out.println(isPalindrome("apple"));
+    System.out.println(isPalindrome("love"));
+    System.out.println(isPalindrome("asdsdfdsafdsgfherfdsa"));
+  }
+}

PictureApp/.gitignore

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+*.iml
+.gradle
+/local.properties
+/.idea/caches
+/.idea/libraries
+/.idea/modules.xml
+/.idea/workspace.xml
+/.idea/navEditor.xml
+/.idea/assetWizardSettings.xml
+.DS_Store
+/build
+/captures
+.externalNativeBuild
+.cxx

PictureApp/app/.gitignore

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+/build

PictureApp/app/build.gradle

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+apply plugin: 'com.android.application'
+
+android {
+  compileSdkVersion 29
+
+  defaultConfig {
+    applicationId "com.example.pictureapp"
+    minSdkVersion 28
+    targetSdkVersion 29
+    versionCode 1
+    versionName "1.0"
+
+    testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
+  }
+
+  buildTypes {
+    release {
+      minifyEnabled false
+      proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
+    }
+  }
+}
+
+dependencies {
+  implementation fileTree(dir: "libs", include: ["*.jar"])
+  implementation 'androidx.appcompat:appcompat:1.1.0'
+  implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
+  testImplementation 'junit:junit:4.12'
+  androidTestImplementation 'androidx.test.ext:junit:1.1.1'
+  androidTestImplementation 'androidx.test.espresso:espresso-core:3.2.0'
+
+}

PictureApp/app/proguard-rules.pro

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+# Add project specific ProGuard rules here.
+# You can control the set of applied configuration files using the
+# proguardFiles setting in build.gradle.
+#
+# For more details, see
+#   http://developer.android.com/guide/developing/tools/proguard.html
+
+# If your project uses WebView with JS, uncomment the following
+# and specify the fully qualified class name to the JavaScript interface
+# class:
+#-keepclassmembers class fqcn.of.javascript.interface.for.webview {
+#   public *;
+#}
+
+# Uncomment this to preserve the line number information for
+# debugging stack traces.
+#-keepattributes SourceFile,LineNumberTable
+
+# If you keep the line number information, uncomment this to
+# hide the original source file name.
+#-renamesourcefileattribute SourceFile