For the given position find the perfect square else make it to next nearest perfect square,then make that to first element and align remaining in ascending order

public class PerfectSquare {

public static void main(String[] args) {
int a[] = {3,12,61,22,78,7};
int sq=0,sqt=0,pos,fp,tmp;
Scanner s = new Scanner(System.in);
System.out.println("Enter the position :");
pos = s.nextInt();
        
/*Making perfect square*/
while(sq != a[pos]){  
        sqt =(int) Math.sqrt(a[pos]);
        sq  = sqt * sqt;
       
        if(sq!=a[pos])
          a[pos]++;
        }

/*Swapping perfect square element to first position*/
fp=a[0];
a[0]=a[pos];
a[pos]=fp;

/*Sorting elements in ascending order - Bubble sort*/
for(int j=0;j<a.length;j++){
for(int k=0;k<a.length;k++){
if(j==0 || k==0)
continue;
if(a[k]>a[j]){
tmp  = a[k];
a[k] = a[j];
a[j] = tmp;
}
}
}

for(int i:a){
System.out.print(i+" ");
}
s.close();
}
}

Output:

Enter the position :
3

25 3 7 12 61 78 

Order the elements of array in consecutive maximum and minimum sequence

public class FirstMaxFirstMin {
void rearrange(int arr[], int n)
{
   // Auxiliary array to hold modified array
   int temp[] = new int[n];
 
   // Indexes of smallest and largest elements
   // from remaining array.
   int small=0, large=n-1;
 
   // To indicate whether we need to copy remaining
   // largest or remaining smallest at next position
   boolean flag = true;
 
   // Store result in temp[]
   for (int i=0; i<n; i++)
   {
       if (flag)
           temp[i] = arr[large--];
       else
           temp[i] = arr[small++];
 
       flag = !flag;
   }
 
   // Copy temp[] to arr[]
   for (int i=0; i<n; i++)
       arr[i] = temp[i];
}

public static void main(String[] args) {
int arr[] = { 1, 2, 3, 4, 5, 6, 7, 8, 9 };
int n = arr.length;
        
FirstMaxFirstMin f=new FirstMaxFirstMin();
 
System.out.println("Original Array");
for (int i = 0; i < n; i++)
System.out.print(arr[i]+" ");

f.rearrange(arr, n);

System.out.println("\nModified Array");
for (int i = 0; i < n; i++)
System.out.print(arr[i]+" ");
}

}

Output:

Original Array
1 2 3 4 5 6 7 8 9 
Modified Array
9 1 8 2 7 3 6 4 5 

Merge Two arrays without duplicates and sort the array to ascending order

import java.util.HashSet;
import java.util.Iterator;
import java.util.Set;

public class MergeArrays {

public static void main(String[] args) {
int a[]={1,2,3,4};
int b[]={10,9,8,7,5,4,0,-6,0,0,0};
int count = 0,temp;

Set<Integer> nodup = new HashSet<Integer>();

for(int i=0;i<a.length;i++){
nodup.add(a[i]);
}
for(int i=0;i<b.length;i++){
nodup.add(b[i]);
}

int f[] = new int[nodup.size()];
int z = 0;

Iterator<Integer> it = nodup.iterator();
while(it.hasNext()){
f[z]=it.next();
z++;
}

for(int l=0;l<f.length;l++){
for(int m=0;m<f.length;m++){
if(f[l]<f[m]){
temp=f[l];
f[l]=f[m];
f[m]=temp;
}
}
}

for(int k=0;k<f.length;k++){
System.out.print(f[k]+" ");
}

}
}

Output:

-6 0 1 2 3 4 5 7 8 9 10 

Pascal's Triangle using Java

import java.util.Scanner;

public class PascalsTriangle {

public static void main(String[] args) {
int rows,coef=1,space,i,j;
Scanner s = new Scanner(System.in);
System.out.println("Enter the number of rows : ");
rows = s.nextInt();
for(i=0;i<rows;i++)
{
for(space=1;space<=rows-i;space++)
{
System.out.print("  ");
}

for(j=0;j<=i;j++)
{
if(i==0 || j==0){
coef=1;
}else{
coef=coef*(i-j+1)/j;
}

System.out.printf("%4d",coef);
}
System.out.println();
}
        s.close();
}
}

Output:

Enter the number of rows : 

5

             1

           1   1

         1   2   1

       1   3   3   1

     1   4   6   4   1