DEV Community: Vasanth S

Practice Program in java Day-10

Vasanth S — Wed, 19 Feb 2025 17:08:43 +0000

Today I learned the new topic of String:
find the length of last word in a string;

program :
class Solution {
public int lengthOfLastWord(String s) {
int last = s.length() - 1;

    while (last >= 0 && s.charAt(last) == ' ') {//to remove he spaces
        last--;
    }

    int start = last;
    while (start >= 0 && s.charAt(start) != ' ') {
        start--;
    }

    return last - start;        
}
public static void main(String... args){
    String a="fly of moon ";
    int S=lengthOfLastWlrd(a);
    System.out.println(S);}

}
}

Playing with HashMap<>(); in java

Vasanth S — Tue, 18 Feb 2025 14:35:29 +0000

Today learned the intresting topic to see is HashMap Concept and play with HashMap are

output:
{2=Apple, 3=Grapes, 4=orange}
{2=Apple, 3=Grapes}
Banana
2
Cherry
0

program:
import java.util.HashMap;
import java.util.Map;

public class hashM {
public static void main(String[] args) {
Map vm=new HashMap<>();//playing with hashmap
vm.put(2,"Apple");
vm.put(3,"Grapes");
vm.put(4,"orange");
System.out.println(vm);
vm.remove(4);
System.out.println(vm);
vm.replace(3,"Banana");
System.out.println(vm.get(3));
System.out.println(vm.size());

    vm.put(4,"Cherry");
    System.out.println(vm.get(4));
    vm.clear();
    System.out.println(vm.size());
}

}

Practice Problem in Java day 9

Vasanth S — Mon, 17 Feb 2025 13:29:10 +0000

Today I covered the sliding window problem to calculate the maximum sum of sub array using kadane's algorithm in java

public class sumofsubarr {
static int max(int a, int b){
return a>b? a : b;
}
public static void main(String[] args) {
int[] arr={1,3,5,2,4,6};
int k=3;
int maxS=0;
int curS=0;
if (k> arr.length) System.out.println(-1);
for (int i=0;i<k;i++) {
curS += arr[i];
}
maxS=curS;
for (int i=k;i< arr.length;i++){//kadanes algorithm
curS=curS+arr[i]-arr[i-k];
maxS=max(maxS,curS);
}

    System.out.println(maxS);
}

}

Practice Program (Java)

Vasanth S — Sat, 15 Feb 2025 14:52:22 +0000

In java today practiced the program of curly braces pattern program

output :
{}
{} {{}}
{} {{}} {{{}}}
{} {{}} {{{}}} {{{{}}}}

public class braces_pattern {
public static void main(String[] args) {
String a="{";
String b="}";
int A=4;
for (int i=1;i<A;i++){
for (int j=1;j<i+1;j++){
for (int k=j;k<=j;k++){
System.out.print(a);
}
for(int k=j;k<=j;k++){
System.out.print(b);
}
}
System.out.println();
}
}
}

java

leetcode

patterns

Practice Program

Vasanth S — Fri, 14 Feb 2025 14:30:02 +0000

In array to remove the given element and print the array as remaining elements

class remove {
public int removeElement(int[] nums, int val) {
int n=0;
for(int i=0;i<nums.length;i++){
if(nums[i]!=val){
nums[n]= nums[i];//store the unique element in an array (n)
n++;
}
}
return n;
}

java

removeelement

Stack Practice in java

Vasanth S — Thu, 13 Feb 2025 14:45:58 +0000

Today practiced the Stack in java and try the problem to check the balanced brackets
here's is an code :

import java.util.Scanner;
import java.util.Stack;
import java.util.StringTokenizer;

public class brackets {
static boolean isvalid(String s){

    Stack<Character> stack=new Stack<>();
    for (char i:s.toCharArray()){
        if(i =='{' || i=='['){
            stack.push(i);
        }
        else {
            if (stack.isEmpty()) {
                return false;
            }
            char top = stack.pop();
            if (i == '}' && top != '{' || i == ']' && top != '[') {
                return false;
            }
        }
    }
    return stack.isEmpty();
}
public static void main(String[] args) {
    Scanner in=new Scanner(System.in);
    System.out.println("Enter the string :");
    String s= in.nextLine();
    System.out.println(isvalid(s));

}

}

java

stack

javastack

balancedstack

leetcode

Practice Programs in java

Vasanth S — Wed, 12 Feb 2025 14:13:51 +0000

Today I had practiced the program roman to integer.
using the switch case to write the give roman and their corresponding integer value to it in a single for loop, if the number the less than the before number (-)otherwise (+).

class Solution {
public int romanToInt(String s) {
int ans = 0, num = 0;
for (int i = s.length() - 1; i >= 0; i--) {
switch (s.charAt(i)) {
case 'I':
num = 1;
break;
case 'V':
num = 5;
break;
case 'X':
num = 10;
break;
case 'L':
num = 50;
break;
case 'C':
num = 100;
break;
case 'D':
num = 500;
break;
case 'M':
num = 1000;
break;
}
if (4 * num < ans)
ans -= num;
else
ans += num;
}
return ans;
}
}

java

romantointeger

roman

leetcode13

leetcode

Practice Programs using Functions

Vasanth S — Fri, 07 Feb 2025 16:18:28 +0000

Today's Practice Programs are
These programs are Practice using a functions.
1.Age Category
program :
import java.util.Scanner;

public class Category {
static String isage(int num)
{
if(num>=50){
return "Your age is above 50";
} else if (num>=40 && num<=50) {
return "Your age is between 40 to 50";
}
else
return "Your age is less than 40";
}
public static void main(String[] args) {
Scanner in=new Scanner(System.in);
System.out.println("Enter the age :");
int age=in.nextInt();
System.out.println(isage(age));

}

**
2.Adding two numbers**
program :
import java.util.Scanner;

public class big_two {
static boolean isgreater(int c, int d){
if(c>d){
return true;
}
return false;

}
public static void main(String[] args) {
    Scanner input=new Scanner(System.in);
    System.out.println("Enter two numbers :");
    int a=input.nextInt();
    int b=input.nextInt();
    if(isgreater(a,b)){
        System.out.println(a+" is greater");
    }
    else{
        System.out.println(b+" is greater");
    }

}

}

**3.Vowel or not
**program :
import java.util.Scanner;
public class vowel {
static boolean vowels(char b){
String s="aeiouAEIOU";
for (int i=0;i<s.length();i++) {
if (b == (s.charAt(i))) {
return true;
}

    }
    return false;
}
public static void main(String[] args) {
    Scanner input = new Scanner(System.in);
    System.out.println("Enter the Character : ");
    char a=input.next().charAt(0);
    if(vowels(a)){
        System.out.println(a+" is vowel");
    }
    else
        System.out.println(a+" is not a vowel");
}

}

4.Good Morning message
program :
import java.util.Scanner;

public class goodM {
static String isgood(int a){
if(a%3==0 && a%4==0){
return "Good Morning";
} else if (a%4==0) {
return "Good afternoon";
} else if (a%3==0) {
return "Good Evening";
}
else
return "Good Night";
}
public static void main(String[] args) {
Scanner in=new Scanner(System.in);
System.out.println("Enter the number :");
int num=in.nextInt();
System.out.println(isgood(num));
}
}

**5.Season
**program :
import java.util.Scanner;

public class season {
static String ismonth(int m){
if(m>=3 && m<=5){
return "Spring Season";
} else if (m>=6 && m<=8) {
return "Summer Season";
} else if (m>=9 && m<=11) {
return "Autumn Season";
} else if (m==12 && m>=1 && m<=2) {
return "Winter Season";
}
else{
return "Invalid input";
}
}
public static void main(String[] args) {
Scanner in=new Scanner(System.in);
System.out.println("Enter a month : ");
int month=in.nextInt();
System.out.println(ismonth(month));

}
}

Diamond Pattern in java;

Vasanth S — Wed, 05 Feb 2025 17:15:04 +0000

Today, I had learned the topic in patterns that is diamond pattern

the output looks like,
The rows=7;

   * 
  * * 
 * * * 
* * * *

* * * * 
 * * *
  * * 
   *

The code in java for above output of diamond pattern is

public class diamond {
public static void main(String[] args) {
int row =7;
for(int i=0;i<row;i++){
for(int j=0;j<row-i;j++){
System.out.print(" ");
}
for(int k=0;k<i+1;k++){
System.out.print("* ");
}
System.out.println();
}
for(int i=0;i<row;i++){
for(int j=0;j<i+1;j++){
System.out.print(" ");
}
for (int k=0;k<row-i;k++){
System.out.print("* ");
}
System.out.println();
}

}

java #pattern #javaprograms #diamondpattern #diamond

Two Pointer(java);

Vasanth S — Tue, 04 Feb 2025 18:08:00 +0000

In Two pointer topic today i have completed the task of finding the happy number in java.

//happy number

public class happy_num {
static boolean happy(int a){

    if(a==1){
        return true;
    }
    else{
        return isHappy(a);
    }
}
public static boolean isHappy(int n) {
    if(n<7 && n>1){//2 
        return false;
    }
    int result=0;
    while(n>0){
        int l=n%10;//rem 
        result+=l*l;//82
        n=n/10;

    }
    if(result==1){
        return true;
    }
    else {
        return happy(result);
    }

}

public static void main(String args[]){
int num=5;
boolean res =isHappy(num);
System.out.println(res);
}

In the above program to find the logic and use recursion technique;

twopointer

java

happynumber

Today's progress on, java

Vasanth S — Thu, 30 Jan 2025 17:18:04 +0000

Today's progress on Java

challenges faced : Issues when solved in problem

today i have solved the date problem successfully and also palindrome of largest string and then perfect number.

aptitude Todays topic is AP /GP got some knowledge about these topics

thankyou for watching this blog.

java task, aptitude;

Vasanth S — Wed, 29 Jan 2025 18:23:14 +0000

Today task I had completed the java basics and also completed the profit & loss.

DEV Community: Vasanth S

Practice Program in java Day-10

Playing with HashMap<>(); in java

Practice Problem in Java day 9

Practice Program (Java)

java

leetcode

patterns

Practice Program

java

removeelement

Stack Practice in java

java

stack

javastack

balancedstack

leetcode

Practice Programs in java

java

romantointeger

roman

leetcode13

leetcode

Practice Programs using Functions

Diamond Pattern in java;

java #pattern #javaprograms #diamondpattern #diamond

Two Pointer(java);

twopointer

java

happynumber

Today's progress on, java

java task, aptitude;

java

profit-loss

aptitude