AriTedeschi

class circularQueue:
    def __init__(self,size,arr):
        # since python doesn`t have arrays i`m using list in place (by default a "list" is a linked list in python)
        self.arr = arr
        
        self.head=0
        self.tail=0
        self.size=size
    
    def next(self,ptr):

AriTedeschi

class circularQueue:
    def __init__(self,size):
        # since python doesn`t have arrays i`m using list in place (by default a "list" is a linked list in python)
        self.arr = []
        
        self.head=0
        self.tail=0
        self.size=size
        for i in range(0,size):
            self.arr.append(None)

AriTedeschi

import java.util.List;
import java.util.Arrays;
import java.util.ArrayList;

public class Main
{
    //O(n)
    public static String twoSum(List numbers, int target){
        Integer head = 0, 
                tail = numbers.size()-1,

AriTedeschi

import java.util.List;
import java.util.ArrayList;

public class Main
{
    public static int prefixSum(List<Integer> numbers, int head, int tail){
		List<Integer> factorialList = new ArrayList<>();
		Integer total = 0;
		for(Integer e : numbers){
		    total += e;

AriTedeschi

import java.util.HashMap;
import java.util.Collections;
import java.util.Map;

public class Main
{
    public interface RepetitionChecker {
        int SingleNumber(int[] sequence);
    }

AriTedeschi

#Linear solution O(n)
#Constant space

def uniqueNumber(sequence) -> int:
    # flags which stores repeated numbers
    # It works for 3 repetions only
    once = 0
    twice = 0
    
    for num in sequence: