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AP1403 - Algorithms/src/main/java/Exercises.java

@@ -8,8 +8,20 @@ public class Exercises {
 
         note: you should return the indices in ascending order and every array's solution is unique
     */
-    public int[] productIndices(int[] values, int target) {
-        // todo
+    public int[] productIndices(int[] values, int target)
+    {
+        int n = values.length;
+        for (int i = 0; i < n; ++i)
+        {
+            for (int j = i + 1; j < n; ++j)
+            {
+             if (values[i] * values[j] == target)
+             {
+                 return new int[] {i, j};
+             }
+            }
+
+        }
         return null;
     }
 
@@ -24,11 +36,49 @@ public int[] productIndices(int[] values, int target) {
 
         so you should walk in that matrix in a curl and then add the numbers in order you've seen them in a 1D array
     */
-    public int[] spiralTraversal(int[][] values, int rows, int cols) {
-        // todo
-        return null;
+    public int[] spiralTraversal(int[][] values, int rows, int cols)
+    {
+        if (values == null || rows == 0 || cols == 0)
+        {
+            return new int[0];
+        }
+        int[] result = new int[rows * cols];
+        int index = 0;
+        int top = 0, bottom = rows - 1;
+        int left = 0, right = cols - 1;
+        while (top <= bottom && left <= right)
+        {
+            for (int i = left; i <= right; i++)
+            {
+                result[index++] = values[top][i];
+            }
+            top++;
+            for (int i = top; i <= bottom; i++)
+            {
+                result[index++] = values[i][right];
+            }
+            right--;
+            if (top <= bottom)
+            {
+                for (int i = right; i >= left; i--)
+                {
+                    result[index++] = values[bottom][i];
+                }
+                bottom--;
+            }
+            if (left <= right)
+            {
+                for (int i = bottom; i >= top; i--)
+                {
+                    result[index++] = values[i][left];
+                }
+                left++;
+            }
+        }
+        return result;
     }
 
+
     /*
         integer partitioning is a combinatorics problem in discreet maths
         the problem is to generate sum numbers which their summation is the input number
@@ -53,12 +103,40 @@ public int[] spiralTraversal(int[][] values, int rows, int cols) {
 
         if you're familiar with lists and arraylists, you can also edit method's body to use them instead of array
     */
-    public int[][] intPartitions(int n) {
-        // todo
-        return null;
+    public class IntegerPartition
+    {
+        public static void main(String[] args)
+        {
+            int n = 4;
+            int[] partition = new int[n];
+            partition(n, n, partition, 0);
+        }
+        public static void partition(int n, int max, int[] partition, int index)
+        {
+            if (n == 0)
+            {
+                printPartition(partition,index);
+                return;
+            }
+
+            for (int i = Math.min(max,n); i >= 1; i--)
+            {
+                partition[index] = i;
+                partition(n - i, i, partition, index + 1);
+            }
+        }
+        public static void printPartition(int[] partition, int length)
+        {
+            for (int i = 0; length > i; i++)
+            {
+                System.out.print(partition[i] + " ");
+            }
+            System.out.println();
+        }
     }
 
-    public static void main(String[] args) {
+    public static void main(String[] args)
+    {
         // you can test your code here
     }
 }

First-Assignment-Algorithms/AP1403 - Algorithms/pom.xml

@@ -0,0 +1,38 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <groupId>org.project</groupId>
+    <artifactId>Algorithms</artifactId>
+    <version>1.0-SNAPSHOT</version>
+
+    <properties>
+        <maven.compiler.source>21</maven.compiler.source>
+        <maven.compiler.target>21</maven.compiler.target>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+    </properties>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter</artifactId>
+            <version>5.11.4</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <pluginManagement>
+            <plugins>
+                <plugin>
+                    <groupId>org.apache.maven.plugins</groupId>
+                    <artifactId>maven-surefire-plugin</artifactId>
+                    <version>3.5.2</version>
+                </plugin>
+            </plugins>
+        </pluginManagement>
+    </build>
+
+</project>

First-Assignment-Algorithms/AP1403 - Algorithms/src/main/java/Exercises.java

@@ -0,0 +1,160 @@
+import java.util.Arrays;
+
+public class Exercises {
+
+    /*
+        there is an array of positive integers as input of function and another integer for the target value
+        all the algorithm should do is to find those two integers in array which their multiplication is the target
+        then it should return an array of their indices
+        e.g. {1, 2, 3, 4} with target of 8 -> {1, 3}
+
+        note: you should return the indices in ascending order and every array's solution is unique
+    */
+    public int[] productIndices(int[] values, int target)
+    {
+        int n = values.length;
+        for (int i = 0; i < n; ++i)
+        {
+            for (int j = i + 1; j < n; ++j)
+            {
+                if (values[i] * values[j] == target)
+                {
+                    return new int[] {i, j};
+                }
+            }
+
+        }
+        return null;
+
+       /* public static void main(String[] args)
+        {
+        int[] values = {2, 5, 1, 4, 10, 69, 420};
+        int target = 420;
+        int[] result = productIndices(values, target);
+
+        if (result.length > 0)
+        {
+            System.out.println("Indices: " + Arrays.toString(result));
+        }
+        else
+        {
+            System.out.println("No pair found.");
+        }
+    }*/
+    }
+
+    /*
+        given a matrix of random integers, you should do spiral traversal in it
+        e.g. if the matrix is as shown below:
+        1 2 3
+        4 5 6
+        7 8 9
+        then the spiral traversal of that is:
+        {1, 2, 3, 6, 9, 8, 7, 4, 5}
+
+        so you should walk in that matrix in a curl and then add the numbers in order you've seen them in a 1D array
+    */
+    public int[] spiralTraversal(int[][] values, int rows, int cols)
+    {
+        if (values == null || rows == 0 || cols == 0)
+        {
+            return new int[0];
+        }
+        int[] result = new int[rows * cols];
+        int index = 0;
+        int top = 0, bottom = rows - 1;
+        int left = 0, right = cols - 1;
+        while (top <= bottom && left <= right)
+        {
+            for (int i = left; i <= right; i++)
+            {
+                result[index++] = values[top][i];
+            }
+            top++;
+            for (int i = top; i <= bottom; i++)
+            {
+                result[index++] = values[i][right];
+            }
+            right--;
+            if (top <= bottom)
+            {
+                for (int i = right; i >= left; i--)
+                {
+                    result[index++] = values[bottom][i];
+                }
+                bottom--;
+            }
+            if (left <= right)
+            {
+                for (int i = bottom; i >= top; i--)
+                {
+                    result[index++] = values[i][left];
+                }
+                left++;
+            }
+        }
+        return result;
+    }
+
+
+    /*
+        integer partitioning is a combinatorics problem in discreet maths
+        the problem is to generate sum numbers which their summation is the input number
+
+        e.g. 1 -> all partitions of integer 3 are:
+        3
+        2, 1
+        1, 1, 1
+
+        e.g. 2 -> for number 4 goes as:
+        4
+        3, 1
+        2, 2
+        2, 1, 1
+        1, 1, 1, 1
+
+        note: as you can see in examples, we want to generate distinct summations, which means 1, 2 and 2, 1 are no different
+        you should generate all partitions of the input number and
+
+        hint: you can measure the size and order of arrays by finding the pattern of partitions and their number
+        trust me, that one's fun and easy :)
+
+        if you're familiar with lists and arraylists, you can also edit method's body to use them instead of array
+    */
+    public class IntegerPartition
+    {
+        public static void main(String[] args)
+        {
+            int n = 4;
+            System.out.println("Integer partitions of " + n + " is:");
+            int[] partition = new int[n];
+            partition(n, n, partition, 0);
+        }
+        public static void partition(int n, int max, int[] partition, int index)
+        {
+            if (n == 0)
+            {
+                printPartition(partition,index);
+                return;
+            }
+            for (int i = Math.min(max,n); i >= 1; i--)
+            {
+                partition[index] = i;
+                partition(n - i, i, partition, index + 1);
+            }
+        }
+        public static void printPartition(int[] partition, int length)
+        {
+            for (int i = 0; length > i; i++)
+            {
+                System.out.print(partition[i] + " ");
+            }
+            System.out.println();
+        }
+    }
+
+    public static void main(String[] args)
+    {
+        // you can test your code here
+    }
+}

First-Assignment-Algorithms/AP1403 - Algorithms/src/test/java/TestPartitions.java

@@ -0,0 +1,65 @@
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+
+public class TestPartitions {
+    static Exercises ex;
+
+    @BeforeAll
+    static void setUp() {
+        ex = new Exercises();
+    }
+
+    @Test
+    void testPartition0() {
+        int[][] expected = {
+                {1}
+        };
+        assertArrayEquals(expected, ex.intPartitions(1));
+    }
+
+    @Test
+    void testPartition1() {
+        int[][] expected = {
+                {4},
+                {3, 1},
+                {2, 2},
+                {2, 1, 1},
+                {1, 1, 1, 1}
+        };
+        assertArrayEquals(expected, ex.intPartitions(4));
+    }
+
+    @Test
+    void testPartition2() {
+        int[][] expected = {
+                {5},
+                {4, 1},
+                {3, 2},
+                {3, 1, 1},
+                {2, 2, 1},
+                {2, 1, 1, 1},
+                {1, 1, 1, 1, 1}
+        };
+        assertArrayEquals(expected, ex.intPartitions(5));
+    }
+
+    @Test
+    void testPartition3() {
+        int[][] expected = {
+                {6},
+                {5, 1},
+                {4, 2},
+                {4, 1, 1},
+                {3, 3},
+                {3, 2, 1},
+                {3, 1, 1, 1},
+                {2, 2, 2},
+                {2, 2, 1, 1},
+                {2, 1, 1, 1, 1},
+                {1, 1, 1, 1, 1, 1}
+        };
+        assertArrayEquals(expected, ex.intPartitions(6));
+    }
+}