Permutaion of word
for ex ABC will be abc , acb,bac,bca,cab,cba
public class Permutation {
public static void main(String[] args) {
String s=”abc”;
List<String>combinations=new ArrayList<String>();
combinations=permutations(s);
System.out.println(combinations);
}
private static List<String> permutations(String s) {
// TODO Auto-generated method stub
List<String>combinations=new ArrayList<String>();
System.out.println(s.length());
if(s.length()==1){
combinations.add(s);
}
else{
System.out.println(“Else part”);
for(int i=0;i<s.length();i++){
List<String>temp=permutations(s.substring(0, i)+s.substring(i+1));
for (String string : temp) {
combinations.add(s.charAt(i)+string);
System.out.println(“s.charAt(i)+string : “+s.charAt(i)+string);
}
}
}
return combinations;
}
}
Reverse Array without additional array
public class ReverseWithoutAdditionalArray {
static void reverseArray(int inputArray[])
{ System.out.println(“Array Before Reverse : “+Arrays.toString(inputArray));
int temp;
for (int i = 0; i < inputArray.length/2; i++)
{
temp = inputArray[i];
inputArray[i] = inputArray[inputArray.length-1-i];
inputArray[inputArray.length-1-i] = temp;
}
System.out.println(“Array After Reverse : “+Arrays.toString(inputArray));
System.out.println(“=========================================”);
}
public static void main(String[] args)
{
reverseArray(new int[]{4, 5, 11, 9, 10})
}
}
Separate zeros from arrays
public class SeparateZero {
public static void main(String[] args) {
int arr[] = {1,2,3,0,5,0,7,8,0};
int newArr[]=new int[arr.length];
int count=0;
for(int i=0;i<arr.length;i++)
{
if(arr[i] != 0)
{
newArr[count]=arr[i];
count++;
}
}
while(count < arr.length)
{
newArr[count]=0;
count++;
}
System.out.println(Arrays.toString(newArr));
}
}
Find unique elements from arrays
Unique elements
for(int i=0;i<arr.length-1;i++)
{ int count =0;
for(int j=1;j<=i;j++)
{
if(arr[i] == arr[j])
{
count++;
}
}
if(count != 1)
{System.out.println(“Duplicate”);
System.out.println(arr[i]);
}
else
{
System.out.println(“Unique”);
System.out.println(arr[i]);
}
}
Add or remove elements from array
int[] my_array = { 25, 14, 56 ,34,12,76};
// Insert an element in 3rd position of the array (index->2, value->5)
//Adding value
int Index_position = 2;
int newValue = 5;
System.out.println(“Original Array : ” + Arrays.toString(my_array));
for (int i = my_array.length-1; i > Index_position; i–) {
my_array[i] = my_array[i-1];
}
my_array[Index_position] = newValue;
System.out.println(“New Array: ” + Arrays.toString(my_array));
//Removing value from array
int [] arr= {5,6,7,8};
int [] newArr=new int[arr.length-1];
int j=6;
int k=0;
for(int i=0;i<arr.length;i++)
{
if(arr[i] != j)
{
newArr[k]=arr[i];
k++;
}
}
System.out.println(Arrays.toString(newArr));
Find missing number
public static void main(String[] args) {
int num[] = { 1, 2, 3, 4, 5, 6, 7, 8, 10 };
int length = num.length;
int nums = length + 1;
int sumno = sumOfNnumbers(nums);
int toatal = sumOfTotalNumber(num);
int missing = toatal – sumno;
System.out.println(“Missing number ” + missing * (-1));
}
static int sumOfNnumbers(int n) {
int sum = 0;
for (int i = 0; i <= n; i++) {
sum = sum + i;
}
return sum;
}
static int sumOfTotalNumber(int arr[]) {
int sums = 0;
for (int i = 0; i < arr.length; i++) {
sums = sums + arr[i];
}
return sums;
}
}
Find Max number from array
for(int i=0;i<arr.length-1;i++)
{
if(arr[i] > max )
{
max=arr[i];
}
}
System.out.println(“Maximum elements :”+max);
for(int i=0;i<arr.length-1;i++)
{
if(arr[i] < min )
{
min=arr[i];
}
}
String:
package in.com;
/*
* with predefined function
* char[] ArrayS1 = s1.toLowerCase().toCharArray();
char[] ArrayS2 = s2.toLowerCase().toCharArray();
Arrays.sort(ArrayS1);
Arrays.sort(ArrayS2);
status = Arrays.equals(ArrayS1, ArrayS2);
*
*/
public class AnagromString {
public static void main(String[] args) {
String str1=”Shubham chivhane”;
String Str2=”chibham Shumhaneqw”;
String s1=str1.replaceAll(“\\s”, ” “);
String s2=Str2.replaceAll(“\\s”, ” “);
if(s1.length() == s2.length())
{
char a1[]=s1.toLowerCase().toCharArray();
char a2[]=s2.toLowerCase().toCharArray();
for(int i=0;i<a1.length;i++)
{
for(int j=i+1;j<a1.length;j++)
{
char tmp;
if(a1[i] > a1[j])
{
tmp=a1[i];
a1[i]=a1[j];
a1[j]=tmp;
}
}
}
for(int i=0;i<a2.length;i++)
{
for(int j=i+1;j<a2.length;j++)
{
char tmp;
if(a2[i] > a2[j])
{
tmp=a2[i];
a2[i]=a2[j];
a2[j]=tmp;
}
}
}
if(a1.equals(a2)) {
System.out.println(“Anagrom”);
}
else
{
System.out.println(“Not Anagrom”);
}
}
else
{
System.out.println(“Not Anagrom”);
}
}
}
Find Number of words in string
public class NumberOfwords {
public static void main(String[] args) {
String str=”aa bb ccc dd ee”;
String [] word=str.split(” “);
System.out.println(“No of word “+ word.length);
}
}————————————————
Find Number of perticular words in string
public class NumberOfwords2 {
public static void main(String[] args) {
String str=”abcf ssd sds “;
char str1=’s’;
int count=0;
for(int i=0;i<str.length();i++)
{
if(str.charAt(i)== str1)
{
count++;
}
}
System.out.println(count);
}
Reverse String and Array
public class ReverseStringAndArray {
public static void main(String[] args) {
int arr[] = {10,20,30,40,50};
int newArr[]= new int[arr.length];
System.out.println(“before reverse Integer Array: “+Arrays.toString(newArr));
int j=0;
for(int i = arr.length -1;i>=0;i–)
{
//System.out.println(arr[i]);
newArr[j] = arr[i];
// System.out.println(newArr[i]);
j++;
}
System.out.println(“reverse Integer Array: “+Arrays.toString(newArr));
String str=”SHUBHAM”;
char a[]=new char[str.length()];
int k=0;
for(int i=str.length()-1;i>=0;i–)
{
a[k]=str.charAt(i);
k++;
}
System.out.println(“String before reverse: “+str);
System.out.println(“reverse string: “+String. valueOf(a));
}
}
find word and their count
public class Test {
public static void main(String[] args) {
String str=”Bread butter and bread”;
String[] words=str.split(” “);
HashMap<String, Integer> hm = new HashMap<>();
for(String word : words)
{
if(hm.containsKey(word))
{
hm.put(word.toLowerCase(), hm.get(word)+1);
}
else
{
hm.put(word.toLowerCase(), 1);
}
}
for(Entry<String, Integer> entry : hm.entrySet())
{
System.out.println(entry.getKey() +” “+entry.getValue());
//if we want duplicate key then we can use it
// if(entry.getValue() > 1)
// {
// System.out.println(“duplicate key only”);
// System.out.println(entry.getKey() +” “+entry.getValue());
// }
}
}
}