Add SpiralMatrix.java to print a matrix in spiral order

Developer.iml

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+<?xml version="1.0" encoding="UTF-8"?>
+<module type="JAVA_MODULE" version="4">
+  <component name="NewModuleRootManager" inherit-compiler-output="true">
+    <exclude-output />
+    <content url="file://$MODULE_DIR$">
+      <sourceFolder url="file://$MODULE_DIR$" isTestSource="false" />
+    </content>
+    <orderEntry type="inheritedJdk" />
+    <orderEntry type="sourceFolder" forTests="false" />
+  </component>
+</module>

Programs/Fibo.java

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+package Programs;
+
+import java.util.*;
+
+public class Fibo {
+
+      public static void main(String[] args) {
+            // Print first n Fibonacci numbers
+            Scanner sc = new Scanner(System.in);
+            System.out.print("Enter number of terms: ");
+            int n = sc.nextInt();
+            sc.close();
+
+            int a = 0, b = 1;
+            System.out.println("Fibonacci Series:");
+            for (int i = 0; i < n; i++) {
+                  System.out.print(a + " ");
+                  int c = a + b;
+                  a = b;
+                  b = c;
+            }
+
+            // Dynamic Programming approach to find nth Fibonacci number
+            int term = 10; // Change this to desired term index
+            System.out.println("\n\n" + term + "th Fibonacci number using DP: " + fibdp(term));
+      }
+
+      // Bottom-up Dynamic Programming approach
+      public static int fibdp(int n) {
+            if (n == 0) return 0;
+            if (n == 1) return 1;
+
+            int[] storage = new int[n + 1];
+            storage[0] = 0;
+            storage[1] = 1;
+
+            for (int i = 2; i <= n; i++) {
+                  storage[i] = storage[i - 1] + storage[i - 2];
+            }
+
+            return storage[n];
+      }
+}

Programs/MajorityElement.java

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+package Programs;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+
+public class MajorityElement {
+      private static List<Integer> majorityElement(int[] v){
+
+            int n = v.length;
+            List<Integer> ans = new ArrayList<>();
+            int min = n/3 +1;
+            HashMap<Integer,Integer> mpp = new HashMap<>();
+
+            for (int j : v) {
+                  int val = mpp.getOrDefault(j, 0);
+                  mpp.put(j, val + 1);
+
+                  if (mpp.get(j) == min) {
+                        ans.add(j);
+                  }
+
+                  if(ans.size() == 2)
+                        break;
+            }
+
+            return ans;
+      }
+
+      public static  void main(String[] args) {
+            int[] arr = {1,2,2,2,1,1};
+            List<Integer> ans = majorityElement(arr);
+            System.out.print("The majority elements are: ");
+            for (Integer an : ans) {
+                  System.out.print(an + " ");
+            }
+            System.out.println();
+      }
+}

Programs/SpiralMatrix.java

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+package Programs;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class SpiralMatrix {
+      public static void main(String[] args){
+            int[][] mat= {{1, 2, 3,4},{5, 6, 7, 8},{9, 10, 11, 12},{13, 14, 15, 16}};
+            List<Integer> ans = spiral(mat);
+            System.out.println(ans);
+      }
+
+      public static List<Integer> spiral(int[][] matrix){
+
+            List<Integer> ans = new ArrayList<>();
+
+            int n = matrix.length, m = matrix[0].length;
+            int left = 0, top = 0;
+            int right = m-1, bottom = n-1;
+
+            while(top<=bottom && left <= right){
+
+                  for(int i = left; i <= right;i++){
+                        ans.add(matrix[top][i]);
+                  }
+                  top++;
+
+                  for(int i = top;i <= bottom; i++){
+                        ans.add(matrix[i][right]);
+                  }
+                  right--;
+
+                  for(int i = right; i >= left; i--){
+                        ans.add(matrix[bottom][i]);
+                  }
+
+                  bottom --;
+
+                  for(int i = bottom; i>= top; i--){
+                        ans.add(matrix[i][left]);
+                  }
+
+                  left++;
+
+            }
+            return ans;
+      }
+}

Programs/TrafficSignal.java

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+package Programs;
+
+class TrafficSignal
+{
+      private String colour;
+
+      private TrafficSignal(String colour)
+      {
+            this.colour=colour;
+      }
+      private boolean isRed()
+      {
+            return colour.equals("red");
+      }
+      private boolean isYellow()
+      {
+            return colour.equals("yellow");
+      }
+      private boolean isGreen()
+      {
+            return colour.equals("green");
+      }
+
+      //Driver Code
+      public static void main(String[] args)
+      {
+            TrafficSignal light=new TrafficSignal("red");
+
+            while(true)
+            {
+                  if(light.isRed())
+                  {
+                        System.out.println("The Signal is red.");
+                        light.colour = "yellow";
+                  }
+                  else if(light.isYellow())
+                  {
+                        System.out.println("The Signal is yellow.");
+                        light.colour = "green";
+                  }
+                  else if(light.isGreen())
+                  {
+                        System.out.println("The Signal is green.");
+                        light.colour = "red";
+                  }
+                  for(int i = 10; i > 0; i--)
+                  {
+                        try{
+                              System.out.print(" "+i);
+                              Thread.sleep(1000);
+                        }catch(InterruptedException e){
+                              System.out.println("Delay not applied.");
+                        }
+                  }
+                  System.out.println();
+                  System.out.print("\033[H\033[2J");
+                  System.out.flush();
+            }
+      }
+}