src/main/java/BonusExercises.java

@@ -54,8 +54,60 @@ public class BonusExercises {
         - has no white-space in it
      */
     public int findValidPasswords(String string) {
-        // todo
-        return -1;
+
+        int validPasswordsCount = 0;
+
+        for (int i = 0; i <= string.length() - 8;) {
+
+            int bestJ = -1;
+
+            for (int j = i + 8; j <= string.length(); j++) {
+                String tempPassword = string.substring(i,j);
+
+                if (tempPassword.contains(" ")){
+                    continue;
+                }
+
+                boolean hasUppercase = false;
+                boolean hasLowercase = false;
+                boolean hasDigit = false;
+                boolean hasSpecialCharacter = false;
+
+                String specialChars = "!@#$%^&*";
+                String digits = "1234567890";
+                String upperCases = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
+                String lowerCases = "abcdefghijklmnopqrstuvwxyz";
+
+                for (int k = 0; k < tempPassword.length(); k++) {
+
+                    char currentChar = tempPassword.charAt(k);
+
+                    if (specialChars.contains(String.valueOf(currentChar))){
+                        hasSpecialCharacter = true;
+                    } else if (upperCases.contains(String.valueOf(currentChar))) {
+                        hasUppercase = true;
+                    } else if (lowerCases.contains(String.valueOf(currentChar))) {
+                        hasLowercase = true;
+                    } else if (digits.contains(String.valueOf(currentChar))) {
+                        hasDigit = true;
+                    }
+                }
+
+                if (hasDigit && hasLowercase && hasUppercase && hasSpecialCharacter){
+                    validPasswordsCount++;
+                    i = j;
+                    bestJ = j;
+                    break;
+                }
+
+            }
+
+            if (bestJ == -1){
+                i++;
+            }
+
+        }
+        return validPasswordsCount;
     }
 
     /*
@@ -66,10 +118,46 @@ public class BonusExercises {
      */
     public List<String> findPalindromes(String string) {
         List<String> list = new ArrayList<>();
-        // todo
+
+
+        String[] wordsArray = string.split("\\s+");
+
+
+        for (String s : wordsArray){
+
+            String cleanedS = s;
+            if (cleanedS.endsWith(",")) {
+                cleanedS = cleanedS.substring(0, cleanedS.length() - 1);
+            }
+            if (cleanedS.isEmpty()) {
+                continue;
+            }
+
+            if (isPalindrome(cleanedS)){
+                list.add(cleanedS);
+            }
+        }
+
+
         return list;
     }
 
+    public boolean isPalindrome(String word) {
+        if (word.length() == 1){
+            return false;
+        }
+        String lowerWord = word.toLowerCase();
+        StringBuilder mutableInverse = new StringBuilder(lowerWord.length());
+
+        for (int i = lowerWord.length() - 1; i >= 0; i--){
+            mutableInverse.append(lowerWord.charAt(i));
+        }
+
+        String inverseOfWord = mutableInverse.toString();
+        return lowerWord.equals(inverseOfWord);
+    }
+
+
     public static void main(String[] args) {
         // you can test your code here
     }

src/main/java/MainExercises.java

@@ -1,3 +1,6 @@
+import java.util.ArrayList;
+import java.util.List;
+
 public class MainExercises
 {
     /*
@@ -20,8 +23,23 @@ public class MainExercises
  */
     public char[][] generateTriangle(int n) {
 
-        // todo
-        return null;
+        char[][] triangle = new char[n][n];
+
+        for (int i = 0; i < n; i++){
+            triangle[i] = new char[i+1];
+            for (int j = 0; j <= i; j++){
+                if (j == 0 ||
+                    i == j ||
+                    i == n -1){
+                    triangle[i][j] = '*';
+                }
+                else {
+                    triangle[i][j] = ' ';
+                }
+            }
+        }
+
+        return triangle;
 
     }
 
@@ -58,8 +76,77 @@ public class MainExercises
            - Number of columns: matrix[0].length (if rectangular)
    */
     public int[] spiralTraversal(int[][] matrix) {
-        // todo
-        return null;
+        int stepedCount = 0;
+        int toSteped = matrix.length * matrix[0].length;
+        boolean[][] steped = new boolean[matrix.length][matrix[0].length];
+
+        for (int i = 0; i < matrix.length; i++) {
+            for (int j = 0; j < matrix[0].length; j++) {
+                steped[i][j] = false;
+            }
+        }
+
+        int[] result = new int[toSteped];
+
+        int currentDir = 0; // 0 : right, 1 : down, 2 : left, 3 : up
+        int currentX = 0, currentY = 0;
+
+        while (stepedCount < toSteped){
+
+            switch (currentDir){
+                case 0:
+                    while (currentX < matrix[0].length && !steped[currentY][currentX]){
+                        steped[currentY][currentX] = true;
+                        result[stepedCount++] = matrix[currentY][currentX];
+                        currentX++;
+                    }
+                    currentX--;
+                    break;
+                case 1:
+                    while (currentY < matrix.length && !steped[currentY][currentX]){
+                        steped[currentY][currentX] = true;
+                        result[stepedCount++] = matrix[currentY][currentX];
+                        currentY++;
+                    }
+                    currentY--;
+                    break;
+                case 2:
+                    while (currentX >= 0 && !steped[currentY][currentX]){
+                        steped[currentY][currentX] = true;
+                        result[stepedCount++] = matrix[currentY][currentX];
+                        currentX--;
+                    }
+                    currentX++;
+                    break;
+                case 3:
+                    while (currentY >= 0 && !steped[currentY][currentX]){
+                        steped[currentY][currentX] = true;
+                        result[stepedCount++] = matrix[currentY][currentX];
+                        currentY--;
+                    }
+                    currentY++;
+                    break;
+            }
+
+            currentDir = (currentDir + 1) % 4;
+
+            switch (currentDir){
+                case 0:
+                    currentX++;
+                    break;
+                case 1:
+                    currentY++;
+                    break;
+                case 2:
+                    currentX--;
+                    break;
+                case 3:
+                    currentY--;
+            }
+
+
+        }
+        return result;
     }
 
     /*
@@ -89,15 +176,52 @@ public class MainExercises
         If you're familiar with Lists and ArrayLists, you can also edit the method's
         body to use them instead of arrays.
     */
-
     public int[][] intPartitions(int n) {
-        // todo
-        return null;
+        List<int[]> result = new ArrayList<>();
+        generatePartitions(n, n, new ArrayList<>(), result);
+        return result.toArray(new int[0][]); // converting a list that consists of arrays into a 2d array
+    }
+
+    private void generatePartitions(int target, int maxValue, List<Integer> current, List<int[]> result) {
+
+        // target : the value that is left from the sum. e.g. n = 4, current = [2,1] then the sum lacks 1 so target = 1
+
+        if (target == 0) {
+            // if we reach target = 0 it means sum of the elements in the current array is the same as target number.
+
+
+            // converting current list into an integer array
+            int[] arr = new int[current.size()];
+
+            for (int i = 0; i < current.size(); i++) {
+                arr[i] = current.get(i);
+            }
+
+            // adding the converted array into result list
+            result.add(arr);
+            return;
+        }
+
+        /* How it works :
+        * we start with the input number as and starting point
+        * then this number can be composed into the greatest number before it (number -1) and 1
+        * now the new maximum number in sum can be composed too.
+        * in order to track all the possible combinations and not just those with 1s i implemented a for loop that goes backward
+        * it's backward so we never get the same array twice.
+        * it starts from minimum of target and maxValue because the maxValue might cause the sum to go beyond the target number.
+        * */
+        for (int i = Math.min(target, maxValue); i >= 1; i--) {
+            current.add(i);
+
+            generatePartitions(target - i, i, current, result);
+
+            // Back tracking
+            current.remove(current.size() - 1);
+        }
     }
 
 
     public static void main()
-    {
-
+    {;
     }
 }