Solutions to Java Data Structures section

Author: sknsht

Java/Data Structures/Java 1D Array/Solution.java

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+import java.util.*;
+
+public class Solution {
+
+    public static void main(String[] args) {
+        Scanner scan = new Scanner(System.in);
+        int n = scan.nextInt();
+
+        int[] a = new int[n];
+
+        for (int i = 0; i < n; i++) {
+            a[i] = scan.nextInt();
+        }
+        scan.close();
+
+        // Prints each sequential element in array a
+        for (int i = 0; i < a.length; i++) {
+            System.out.println(a[i]);
+        }
+    }
+}

Java/Data Structures/Java 2D Array/Solution.java

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+import java.util.*;
+
+public class Solution {
+
+    public static void main(String[] args) {
+        Scanner sc = new Scanner(System.in);
+        int[][] a = new int[6][6];
+        int max = Integer.MIN_VALUE;
+
+        for (int i = 0; i < 6; i++) {
+            for (int j = 0; j < 6; j++) {
+                a[i][j] = sc.nextInt();
+                if (i > 1 && j > 1) {
+                    int sum = a[i][j] 
+                            + a[i][j - 1] 
+                            + a[i][j - 2] 
+                            + a[i - 1][j - 1] 
+                            + a[i - 2][j] 
+                            + a[i - 2][j - 1] 
+                            + a[i - 2][j - 2];
+
+                    if (sum > max)
+                        max = sum;
+                }
+            }
+        }
+
+        sc.close();
+        System.out.println(max);
+    }
+}

Java/Data Structures/Java Arraylist/Solution.java

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+import java.util.*;
+
+public class Solution {
+
+    public static void main(String[] args) {
+        Scanner in = new Scanner(System.in);
+        int n = in.nextInt();
+        ArrayList<ArrayList<Integer>> rows = new ArrayList<>();
+
+        for (int i = 0; i < n; i++) {
+            int m = in.nextInt();
+            ArrayList<Integer> row = new ArrayList<>();
+
+            for (int j = 0; j < m; j++) {
+                row.add(in.nextInt());
+            }
+            rows.add(row);
+        }
+        n = in.nextInt();
+        for (int i = 0; i < n; i++) {
+            int x = in.nextInt();
+            int y = in.nextInt();
+            try {
+                System.out.println(rows.get(x - 1).get(y - 1));
+            } catch (Exception e) {
+                System.out.println("ERROR!");
+            }
+        }
+    }
+}

Java/Data Structures/Java Subarray/Solution.java

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+import java.util.*;
+
+public class Solution {
+
+    public static void main(String[] args) {
+        Scanner sc = new Scanner(System.in);
+        int n = sc.nextInt();
+        int[] a = new int[n];
+
+        for (int i = 0; i < n; i++) {
+            a[i] = sc.nextInt();
+        }
+        sc.close();
+
+        int negativeSubarrays = 0;
+        for (int i = 0; i < n; i++) {
+            int sum = 0;
+            for (int j = i; j < n; j++) {
+                sum += a[j];
+                if (sum < 0) {
+                    negativeSubarrays++;
+                }
+            }
+        }
+        System.out.println(negativeSubarrays);
+    }
+}