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src/main/java/com/zipcodewilmington/assessment1/part1/BasicArrayUtils.java

@@ -9,30 +9,36 @@ public class BasicArrayUtils {
      * @return the first element in the array
      */
     public static String getFirstElement(String[] stringArray) {
-        return null;
+        return stringArray[0];
+
+        //return null;
     }
 
     /**
      * @param stringArray an array of String objects
      * @return the second element in the array
      */
     public static String getSecondElement(String[] stringArray) {
-        return null;
+       return stringArray[1];
+        //return null;
     }
 
     /**
      * @param stringArray an array of String objects
      * @return the last element in the array
      */
     public static String getLastElement(String[] stringArray) {
-        return null;
+        return stringArray[stringArray.length-1];
+
+        //return null;
     }
 
     /**
      * @param stringArray an array of String objects
      * @return the second to last element in the array
      */
     public static String getSecondToLastElement(String[] stringArray) {
-        return null;
+        return stringArray[stringArray.length-2];
+        //return null;
     }
 }

src/main/java/com/zipcodewilmington/assessment1/part1/BasicStringUtils.java

@@ -9,23 +9,31 @@ public class BasicStringUtils {
      * @return string with identical content, and the first character capitalized
      */
     public static String camelCase(String str) {
-        return null;
+        //char firstChar = str.toUpperCase(str.charAt(0);
+        //String outcome = new StringBuilder(str).setCharAt(0, );
+        String outcome = Character.toUpperCase(str.charAt(0)) + str.substring(1);
+        return outcome;
+        //return null
     }
 
     /**
      * @param str string input from client
      * @return string with identical contents, in the reverse order
      */
     public static String reverse(String str) {
-        return null;
+        String outcome = new StringBuilder(str).reverse().toString();
+        return outcome;
+        //return null;
     }
-
     /**
      * @param str string input from client
      * @return string with identical contents, in reverse order, with first character capitalized
      */
     public static String reverseThenCamelCase(String str) {
-        return null;
+        String step1reverse = reverse(str);
+        String step2camel = camelCase(step1reverse);
+        return step2camel;
+        //return null;
     }
 
 
@@ -34,14 +42,31 @@ public static String reverseThenCamelCase(String str) {
      * @return string with identical contents excluding first and last character
      */
     public static String removeFirstAndLastCharacter(String str) {
-        return null;
+        //str = str.substring(1,str.length()-1);
+        StringBuilder sb = new StringBuilder(str);
+        sb.deleteCharAt(str.length()-1);
+        sb.deleteCharAt(0);
+        return sb.toString();
+        // String outcome = str.replace(str.charAt(0),'');
+       // return null;
     }
 
     /**
      * @param str a string input from user
      * @return string with identical characters, each with opposite casing
      */
     public static String invertCasing(String str) {
-        return null;
+        char[] chars = str.toCharArray();
+        //loop through the char to reverse each
+        for (int i = 0; i < chars.length; i++) {
+            char c = chars[i];
+            if (Character.isUpperCase(c)) {
+                chars[i] = Character.toLowerCase(c);
+            } else if (Character.isLowerCase(c)) {
+                chars[i] = Character.toUpperCase(c);
+            }
+        }
+        return new String(chars);
+        //return null;
     }
 }

src/main/java/com/zipcodewilmington/assessment1/part1/IntegerArrayUtils.java

@@ -1,5 +1,8 @@
 package com.zipcodewilmington.assessment1.part1;
 
+import java.util.Arrays;
+import java.util.stream.IntStream;
+
 /**
  * Created by leon on 2/16/18.
  */
@@ -9,22 +12,39 @@ public class IntegerArrayUtils {
      * @return the sum of `intArray`
      */
     public static Integer getSum(Integer[] intArray) {
-        return null;
+        int sum = 0;
+        for (int num : intArray){
+            sum += num;
+        }
+        return sum;
+        //Integer sum = intArray.stream();
+        //int sum = IntStream.of(intArray).sum();
+        //return Arrays.stream(intArray).sum();
+        //return null;
     }
 
     /**
      * @param intArray an array of integers
      * @return the product of `intArray`
      */
     public static Integer getProduct(Integer[] intArray) {
-        return null;
+        int product =1;
+        for (int i : intArray){
+            product *=i;
+        }
+        return product;
+        //return null;
     }
 
     /**
      * @param intArray an array of integers
      * @return the sum of `intArray` divided by number of elements in `intArray`
      */
     public static Double getAverage(Integer[] intArray) {
-        return null;
+        double averg = getSum(intArray);
+        averg /= (intArray.length);
+        return averg;
+
+        //return null;
     }
 }

src/main/java/com/zipcodewilmington/assessment1/part1/IntegerUtils.java

@@ -11,22 +11,43 @@ public class IntegerUtils {
      * @return the sum of all integers between 0 and not including `n`
      */
     public static Integer getSumOfN(Integer n) {
-        return null;
+        int N = n;
+        int sum = 0;
+        for (int i =1; i <=N;i++){
+            sum +=i;
+        }
+        return sum;
+        //return null;
     }
 
     /**
      * @param n integer value input by client
      * @return the product of all integers between 0 and not including `n`
      */
     public static Integer getProductOfN(Integer n) {
-        return null;
+        long outcome = 1;
+        for (int factor = 2; factor <= n; factor++) {
+            outcome *= factor;
+        }
+        return Math.toIntExact(outcome);
+        //return null;
     }
 
     /**
      * @param val integer value input by client
      * @return integer with identical digits in the reverse order
      */
     public static Integer reverseDigits(Integer val) {
-        return null;
+            int reverse = 0;
+            while (val !=0){
+                reverse = reverse * 10 + val % 10;
+                val/=10;
+            }
+            return reverse;
+//        int digits = val;
+//        StringBuilder newDigits = new StringBuilder(String.valueOf(digits));
+//        digits = newDigits.reverse();
+
+        //return null;
     }
 }

src/main/java/com/zipcodewilmington/assessment1/part1/RockPaperSissorsEvaluator.java

@@ -13,15 +13,31 @@ public class RockPaperSissorsEvaluator {
      * @return the respective winning move
      */
     public String getWinningMove(String handSign) {
-        return null;
+        if (handSign == "rock") {
+            return "paper";
+        }
+        else if (handSign == "scissors"){
+            return "rock";
+        }
+        else return "scissors";
+        //return null;
+
     }
 
     /**
      * @param handSign a string representative of a hand sign
      * @return the respective losing move
      */
     public String getLosingMove(String handSign) {
-        return null;
+        if (handSign == "rock") {
+            return "scissor";
+        }
+        else if (handSign == "scissor"){
+            return "paper";
+        }
+        else return "rock";
+
+        //return null;
     }
 
     /**
@@ -30,6 +46,17 @@ public String getLosingMove(String handSign) {
      * @return a string representative of the winning hand sign between the two players
      */
     public String getWinner(String handSignOfPlayer1, String handSignOfPlayer2) {
-        return null;
+        if (handSignOfPlayer1 == "rock" && handSignOfPlayer2 == "scissor") {
+            return "rock";
+        }
+        else if (handSignOfPlayer1 == "scissor" && handSignOfPlayer2 == "paper"){
+            return "scissor";
+        }
+        else if (handSignOfPlayer1 == "paper" && handSignOfPlayer2 == "rock"){
+            return "paper";
+        }
+        else return handSignOfPlayer2;
+
+        //return null;
     }
 }

src/main/java/com/zipcodewilmington/assessment1/part2/ArrayUtils.java

@@ -1,5 +1,9 @@
 package com.zipcodewilmington.assessment1.part2;
 
+import java.util.Arrays;
+import java.util.stream.Stream;
+import java.util.HashMap;
+import java.util.Map;
 /**
  * Created by leon on 2/16/18.
  */
@@ -11,7 +15,16 @@ public class ArrayUtils {
      * Given an array of objects, named `objectArray`, and an object `objectToCount`, return the number of times the `objectToCount` appears in the `objectArray`
      */
     public static Integer getNumberOfOccurrences(Object[] objectArray, Object objectToCount) {
-        return null;
+        // loop through
+        int counter = 0;
+        for (int i = 0; i <objectArray.length; i++) {
+            // conditional
+            if (objectArray[i].equals(objectToCount)) {
+                counter++;
+            }
+        }
+        return counter;
+        //return null;
     }
 
     /**
@@ -20,8 +33,30 @@ public static Integer getNumberOfOccurrences(Object[] objectArray, Object object
      * @return an array with identical content excluding the specified `objectToRemove`
      * Given an array of objects, name `objectArray`, and an object `objectToRemove`, return an array of objects with identical contents excluding `objectToRemove`
      */
-    public static Object[] removeValue(Object[] objectArray, Object objectToRemove) {
-        return null;
+    public static Integer[] removeValue(Integer[] objectArray, Integer objectToRemove) {
+        int x = 0;
+        for (int i =0; i <objectArray.length; i++){
+            //check if element i matches value
+            //use ! to reverse the locic equals
+            if (!objectArray[i].equals(objectToRemove)) {
+                //if no match to remove, go to next array element
+                x++;
+            }
+        }
+        //create empty fixed array
+        Integer[] fixedArray = new Integer[x];
+        int y = 0;
+        //build array with a loop
+        for (int i=0; i<objectArray.length;i++){
+            if (!objectArray[i].equals(objectToRemove)){
+                //as long as no match to remove
+                fixedArray[y++] = objectArray[i];
+            }
+        }
+        return fixedArray;
+        //return null;
+
+
     }
 
     /**
@@ -30,17 +65,53 @@ public static Object[] removeValue(Object[] objectArray, Object objectToRemove)
      * given an array of objects, named `objectArray` return the most frequently occuring object in the array
      */
     public static Object getMostCommon(Object[] objectArray) {
-        return null;
-    }
+        Map<Integer, Integer> countMap = new HashMap<>();
+        int mostFrequent = (int) objectArray[0];
+        int maxCount = 0;
 
+        for (int i = 0; i < objectArray.length; i++) {
+            int num = (int) objectArray[i];
+            int count = countMap.getOrDefault(num, 0) + 1;
+            countMap.put(num, count);
 
+            if (count > maxCount) {
+                mostFrequent = num;
+                maxCount = count;
+            }
+        }
+        return mostFrequent;
+        //return null;
+    }
     /**
      * @param objectArray an array of any type of Object
      * @return the least frequently occurring object in the array
      * given an array of objects, named `objectArray` return the least frequently occuring object in the array
      */
-    public static Object getLeastCommon(Object[] objectArray) {
-        return null;
+    public static Object getLeastCommon(Integer[] objectArray) {
+        int n = objectArray.length;
+        boolean visited[] = new boolean[n];
+        int maxFreq = 0, minFreq = n;
+        int maxElement = 0, minElement = 0;
+        for (int i = 0; i < n; i++) {
+            if (visited[i] == true)
+                continue;
+            int count = 1;
+            for (int j = i + 1; j < n; j++) {
+                if (objectArray[i] == objectArray[j]) {
+                    visited[j] = true;
+                    count++;
+                }
+            }
+            if (count > maxFreq) {
+                maxElement = objectArray[i];
+                maxFreq = count;
+            }
+            if (count < minFreq) {
+                minElement = objectArray[i];
+                minFreq = count;
+            }
+        }
+        return minElement;
     }
 
     /**
@@ -50,6 +121,15 @@ public static Object getLeastCommon(Object[] objectArray) {
      * given two arrays `objectArray` and `objectArrayToAdd`, return an array containing all elements in `objectArray` and `objectArrayToAdd`
      */
     public static Object[] mergeArrays(Object[] objectArray, Object[] objectArrayToAdd) {
-        return null;
+        int x = objectArray.length;
+        int y = objectArrayToAdd.length;
+        Integer[] mergeArray = new Integer[x + y];
+
+        System.arraycopy(objectArray, 0, mergeArray, 0, x);
+        System.arraycopy(objectArrayToAdd, 0, mergeArray, x, y);
+
+        System.out.println(Arrays.toString(mergeArray));
+        return mergeArray;
+        //return null;
     }
 }