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Logical Interview Questions and Answers

Logical Interview Questions and Answers


Logic-based interview puzzles are becoming increasingly popular in recruitment processes to help employers find the brightest candidates and gain insight into a candidate’s thought process.

1. Find FaboconiSeries?

public static void FaboconiSeries()
 {
 int n=10;
 int a=0;
 int b=1;
 System.out.println(a+","+b);
 for(int i=0;i<n;i++)
 {
int c=a+b;
 a=b;
 b=c;
 System.out.println(c+".................FaboconiSeries");
 }
  }

2. Find ArmstrogNumber?

public void ArmstrogNumber()
 {
 int n=153;
 int temp=n;

 int sum=0;
 while(temp!=0)
 {
int a=temp%10;
sum=sum+a*a*a;
temp=temp/10;
 }
 if(sum==n)
 {
 System.out.println("yes................ArmstrogNumber");
 }
 }

3. Find Factorial?

 public void Factorial()
 {
 int n=5;
   int a=1;
for(int i=1;i<=n;i++)
{System.out.println(a+","+i);
a=a*i;
System.out.println(a+","+i);
}
System.out.println(a+".................Factorial");
 }

4. Find Reversestring?

public void reversestring()
 {
 //using n
 String s="akshay";
 char[] ch=s.toCharArray();
 for(int i=ch.length-1;i>=0;i--)
 {
 System.out.print(ch[i]);
 }

 //using n/2

 String s1="akshay";
 char[] ch1=s1.toCharArray();
 for(int i=0;i<=ch1.length/2;i++)
 {
 char temp=ch1[i];
 ch1[i]=ch1[ch1.length-i-1];
 ch1[ch1.length-i-1]=temp;
 }
 System.out.println(Arrays.toString(ch1));
 }

5. Find using recursion reverse?

//using recursion reverse
 public static String stringreverse(String str)
 {
 String s1="a";
 String s2="a";
 if(s1.equals(s2))
 {
 System.out.println("true");
 }
 if(str.isEmpty())
 {
 return str;

 }
return stringreverse(str.substring(1))+str.charAt(0);
 }

6. Find Occurance Of Array?


 public void occurance()
 {
 int[] array= {1,2,3,1,4,1,1,2,3,4,5,5,4};

 HashSet<Integer> hs = new HashSet<>();
 for(int i=0;i<array.length;i++) {
 hs.add(array[i]);
 }

 for(int c:hs)
 {
 int count=0;
 for(int j=0;j<array.length;j++)
 {
 if(c==array[j])
 {
 count++;
 }
 }
 System.out.println(c+"occurance is:=="+count);
 }
 }
}

#Common Class And Main Method For Calling All Methods Above.

import java.util.Arrays;
import java.util.HashSet;

abstract public class Logical
{
 public static void main(String[] args)
 {
       Logical l=new Logical();
      l.occurance();                                  // Calling Accurance
       String t=l.stringreverse("akshay");
       System.out.println(t);                        //Calling Reverse String
       l.FaboconiSeries();                              //Calling Faboconi Series
       l.ArmstrogNumber();                         //Calling Armstrong Number
       l.Factorial();                                        //Calling Factorial
      l.reversestring();                                  //Calling Reverstring
 Logical.FaboconiSeries();
 }

7.occurance of string character.

import java.util.*;
public class HelloWorld
{ 
 public static void main(String []args)
{
   System.out.println("Hello World");
   String str="abcdeabscderdscaaaaa";
   char[] arr=str.toCharArray();
   HashSet<Character> hs= new HashSet(); 
   for(int i=0;i<arr.length;i++)
   {   
    hs.add(arr[i]);
    } 
   System.out.println(hs);
   for(char set:hs)
    {
         int count=0;
         for(int j=0;j<arr.length;j++)
   {
          if(set==arr[j])
           count++;
   }   
  System.out.println(set+"::occurance is:"+count);
 }
     }
}

8.The occurrence of number.

import java.util.*;
public class HelloWorld
{
     public static void main(String []args){
     System.out.println("Hello World");
     int a[]={3,4,2,3,5,6,7,2,3,4,4,56};
     HashSet<Integer> a1=new HashSet<Integer>();
     for(int i=0;i<a.length;i++)
     {
            a1.add(a[i]);
      }
     System.out.println(a1);
     for(int set:a1)
     {        int count=0;

             for(int j=0;j<a.length;j++)
            {
                if(set==a[j])
                {
                    count++;
                }
            }
       System.out.println(set+"occuerance is:"+count);
        }
     }
}

 9.The occurrence of number by key.

import java.util.*;
public class HelloWorld
{
        public static void main(String []args){
        System.out.println("Hello World");
        int a[]={3,4,2,3,5,6,7,2,3,4,4,56};
        int x=5;
        int count=0;
        for(int i=0;i<a.length;i++)
        {
            if(x==a[i])
            {
                count++;
            }
        }
   System.out.println("occurence is:"+count);
 }
}

10.largest number.

//by using list.size()-1
import java.util.*;
public class HelloWorld
{
  public static void main(String []args)
  {
  System.out.println("Hello World"); 
   int[] a={11,23,34,56,76,78,33,12};
  TreeSet<Integer> a1=new TreeSet<Integer>();
    for(int i=0;i<a.length;i++)
   {
            a1.add(a[i]);
    }
  System.out.println(a1);
 List<Integer> list= new ArrayList<Integer>(a1);
  System.out.println(list.get(list.size()-1));
  }
}

//method-2
import java.util.*;
public class HelloWorld
{
   public static void main(String []args)
  {
   System.out.println("Hello World"); 
   double[] numArray = {34,23,65,33,76,90,112,43};
   double search = numArray[0];
    for (int i=0;i<numArray.length;i++)
    {
        if(search < numArray[i])
        search = numArray[i];
     }
   System.out.format("Largest element = %.2f", search);
  }
}

11. Convert String to Int Without using ParseInt() Method.

    public class StringToInteger
   {
    public static void main(String[] args)
    {
        int i = convertToInt("123679");
        System.out.println("String decoded to number " + i);
    }
    public static int convertToInt(String input)
   {
        char[] ch=input.toCharArray();
        int sum=0;
       for(char c:ch)
       {
           sum=(sum*10)+(int)c -(int)'0';
       }
       return sum;
    }
}

12.reverse String in Size/2.

public class ReverseString
 {
public static void main(String[] args)
{
Scanner input=new Scanner(System.in);
System.out.println("Please enter String");
String str=input.nextLine();
char[] myarray=str.toCharArray();
int size=myarray.length;
char[] original=Arrays.copyOf(myarray, size);
for(int i=0;i<size/2;i++)
{
char temp= myarray[i];
myarray[i]=myarray[size-i-1];
myarray[size-i-1]=temp;
}
System.out.println("orignal array is:"+Arrays.toString(original));
System.out.println("reverse array is"+Arrays.toString(myarray));
}

}

13.Reverse string.

  public class HelloWorld
 {
       public static void main(String []args){
       String str="ashish";
       char[] test=str.toCharArray();
       for(int i=test.length-1;i>=0;i--)
      {
        System.out.println(test[i]);
      }
    }
}

14.Reverse Integer

import java.util.*;
public class HelloWorld
{
     public static void main(String []args)
     {
      int a=4567896;
      int reverse=0;
     System.out.println("integer is:"+a);
      while(a !=0)
        {
          reverse=reverse*10 +a%10;
           a=a/10;
        }
        System.out.println("reverse is"+reverse);
     }
}

15.Devide without Mod.

package org.ashish;
import java.util.*;
public class DivideWithoutMod
{
 public static void main(String[] args)
{
 Scanner input=new Scanner(System.in);
 System.out.println("Enter Divident");
 int divident=input.nextInt();
 System.out.println("Enter Divisor");
 int divisor=input.nextInt();
 int Qoutient=0;
 while(divident>=divisor)
{
divident=divident-divisor;
Qoutient++;

}
System.out.println("Remainder is:"+divident);
System.out.println("Qoutient is:"+Qoutient);
}
}

16.Ascending Order.

import java.util.Arrays;
public class HelloWorld
{
 public static void main(String []args)
{     
   System.out.println("Hello World");
   int numb=7;
   int[]arr={4,2,1,6,7,5,3};
   System.out.println("original array is:"+Arrays.toString(arr));
   int temp; 
  for(int i=0;i<numb-1;i++)
  {
      for(int j=0;j<numb-i-1;j++)
     {                 
        if(arr[j]>arr[j+1])
        {
           temp=arr[j];
           arr[j]=arr[j+1];
           arr[j+1]=temp;       
          }     
      }     
 }
        System.out.println("Sorted array is:"+Arrays.toString(arr)); 
 }
}

17.Araay Union and Intersection by Hashing.

import java.util.HashSet;
// Java program to find union and intersection
// using Hashing
class Main
{ 
    // Prints union of arr1[0..m-1] and arr2[0..n-1]
      static void Union(int a[],int b[])
     {
       HashSet<Integer> hs= new HashSet<>(); 
       for(int i=0;i<a.length;i++)
       hs.add(a[i]);
       for(int j=0;j<b.length;j++)
       hs.add(b[j]);
       System.out.println(hs);
     }
     static void Intersection(int a[],int b[])
    {
        HashSet<Integer> hs=new HashSet<>();
        for(int i=0;i<a.length;i++)
        hs.add(a[i]);
        for(int j=0;j<b.length;j++)
        if(hs.contains(b[j]))
        System.out.println(b[j]+"");
     }
   
// Prints intersection of arr1[0..m-1] and arr2[0..n-1]
// Driver method to test the above function
   public static void main(String[] args)
  {
        int a[] = {7, 1, 5, 2, 3, 6};
        int b[] = {3, 8, 6, 20, 7};
        System.out.println("Union of two arrays is : ");
        Union(a,b);
        System.out.println("Intersection of two arrays is : ");
        Intersection(a,b);     
  }
}

18.Iterator & List

Public class test
{
 public static void main(String []args)
{
  System.out.println("Hello World");   
  ArrayList<String> al = new ArrayList<String>(5); 
 al.add("ashish");
 al.add("anita");     
 al.add("ashu");   
 al.add("suniti");   
 al.add("sandip"); 
 al.add("sonal"); 
 System.out.println("original Content of al is:");
 Iterator it= al.iterator();
 while(it.hasNext()) 
 {
   Object elem=it.next();
   System.out.println("Name:"+elem);
  }
ListIterator lit=al.listIterator();
while(lit.hasNext())
{
     Object elem=lit.next();
      lit.set(elem+"test");
      System.out.println("after modification al is:");
   
    it= al.iterator();
   while(it.hasNext())
   {
          Object elem=it.next();
          System.out.println("Name:"+elem);
   }
   while(lit.hasPrevious())
  {
        Object elem=lit.previous();
         System.out.println(elem+"");
   }
  }
}

19.String anagram.

import java.util.*;
public class HelloWorld
{
 public static void main(String []args){
 System.out.println("Hello World");
 boolean status=true;
 String str="keep";
 String str1="peek";
 if(str.length()!=str1.length())
 {
   status=false;
  }
  else{
     char[] chr=str.toLowerCase().toCharArray();
     char[] chr1=str1.toLowerCase().toCharArray();
     Arrays.sort(chr);
     Arrays.sort(chr1);
    status=Arrays.equals(chr,chr1);
}
if (status)
{
  System.out.println(str + " and " + str1 + " are anagrams");
 }
  else{
           System.out.println(str + " and " + str1 + " are not anagrams");
        }
    }
}

20. Mixed Array addition finds occurrence.

import java.util.*;
public class HelloWorld
{
public static void main(String []args){
System.out.println("Hello World");
int[] arr={1,2,3,-1,2,4,3,2};
int sum;
ArrayList list =new ArrayList();
for(int i=0;i<arr.length;i++)
{
  for(int j=1+i;j<arr.length;j++)
  {
     sum=arr[i]+arr[j];
     list.add(sum);
   }
  }
  System.out.println(list);
   int length=list.size();
   HashSet<Integer> hs=new HashSet(list);
   System.out.println(hs);
   for(Object set:hs)
  {
   int count=0;
  for(int i=0;i<length;i++)
 {
    if(set==list.get(i))
   {
        count++;
    }
  }
    System.out.println(set+":occurance is:"+count);
 }
}
}

21.LowerCase to UperCase and Upper to lower.

import java.util.*;
public class HelloWorld{
public static void main(String []args)
{
  System.out.println("Hello World");
  StringBuffer str= new StringBuffer("KeepReady");
  convertOpposite(str);
  System.out.println(str);
  }
 public static void convertOpposite(StringBuffer str)
 {
   for(int i=0;i<str.length();i++)
   {
     Character c=str.charAt(i);
     if(Character.isLowerCase(c))
      {
         str.replace(i, i+1, Character.toUpperCase(c)+"");
      }
     else{
            str.replace(i, i+1, Character.toLowerCase(c)+""); 
           }
        }
}

22.String Length without length method.

public class Main
{
 public static void main(String[] args)
 {
System.out.println("Hello World");
String str="abcde";
int count=0;
for(char c:str.toCharArray())
{
  count++;  
}
System.out.println(count);
}
}

23. Write Custom Exception .

 class myException extends Exception
{
     myException(String s)
    {
        super(s);
    }
}
public class Main
{
     static void validate(int age) throws myException
    {
        if(age<18)
        {
            throw new myException("under age need id proof");
        }
        else{
                throw new myException("above 18 ok");
               }
      public static void main(String[] args)
      {
System.out.println("Hello World");
try{
validate(19);
}
catch(Exception e)
{
    System.out.println(e);
}
}
}

24.Custom_Thread.

1.By implementing Runnable Interface:

public class Main implements Runnable
{
    public void run()
   {
System.out.println("thread running");
    }
     public static void main(String[] args)
    {
           System.out.println("Hello World");
Main m = new Main();
Thread t= new Thread(m);
t.start();
     }
}

2.By extending Thread Class:

public class Main extends Thread
{
    public void run(){
System.out.println("thread running");
    }
    
public static void main(String[] args) {
System.out.println("Hello World");
Main m = new Main();
m.start();
}
}

24.Write MVC configuration-XML based

1.Dispatcher Servlet configuration(web.xml)

<servlet>
<servlet-name>Spring</servlet-name>
<servlet-class> org.springframework.web.servlet.DispatcherServlet</servlet-class>
</servlet>

<servlet-mapping>
<servlet-name>spring</servlet-name>
 <url-pattern>/</url-pattern>
</servlet-mapping>

2.Spring web configuration File(Spring-servlet.xml)

<beans>
<context:component-scan base-package = "com.tutorialspoint" />
<bean class = "org.springframework.web.servlet.view.InternalResourceViewResolver">
      <property name = "prefix" value = "/WEB-INF/jsp/" />
      <property name = "suffix" value = ".jsp" />
   </bean>
<bean>
<bean>
</beans>

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