CareerCup

Put items in a hash table one by one. If any item repeats then dont put it. Give back the hash table. Its uniques

4 ways

1)hash table....
2)sorting
3)two loops
4) if range is known then after visiting every element, mark it visited either by changing its sign or doubling it...

use STL set to uniquely create a set and remove duplicate element from the array

Build a Binary Search Tree.

dont post inbuilt solutions like wit STL .. no company wants us to code with predefined functions..they jus wanna code from scratch..STL map is implemented wit balanced BST..complexity wud obviously be O(n log n)

use idea of counting sort

// Arr = initial array, Len = initial array length, pRes = pointer to the result array, resLen = length of the result array

template <class T>
void RemoveDuplicatesFromArray(T Arr[], T Len, T*&pRes, T&ResLen)
{
	int i;
	bool bExists;
	T* pCurrent;

	if(Len==0)
	{
		pRes=NULL;
		ResLen=0;
		return;
	}

    pRes = new T[Len]; 

	// Always put the first element
	*pRes = Arr[0];
	ResLen=1;

	// then check the result array - do we already have such element?
	for(i=1;i<Len;i++)
	{
		pCurrent = pRes;
		bExists=false;

		do
		{
			if(*pCurrent == Arr[i])
			{
				bExists=true; // found the same element in result array
				break;
			}
			pCurrent++;
		} while(pCurrent < pRes+ResLen);

		if(bExists==false)
		{
			*pCurrent = Arr[i]; // add the element to the result array
			ResLen++;
		}
	} // end of "for"
}

In an array of char:

std::string removeDuplicateChar(const std::string& str)
{
	std::string result;
	typedef std::bitset<__SCHAR_MAX__ * 2U + 1> Bitset;
	Bitset bitset;

	std::string::const_iterator it = str.begin(), end = str.end();
	for (; it != end; ++it)
	{
		Bitset::reference ref = bitset[*it];
		if (!ref)
		{
			result += *it;
		}

		ref = 1;
	}

	return result;
}

import java.util.*;

class deldupchar
{
public static void main(Srtring[] args)
{
ary a={1,3, 6, 67, 3, 5 , 8};
Arrays.sort(a);// a={1,3,3,5,6,8,67}
for(int i=0;i<a.length-2;i++)
{
if(a[i]==a[i+1])
{
if((i+2)!=a.length+1)
{
a[i+1]=a[i+2];
}
a[i+1]=NULL;
}
}
}

package com.linus.interview.algo;

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

public class RemoveDuplicates {

/**
* @param args
*/
public static void main(String[] args) {
int[] arr = { 1, 3, 4, 1, 2, 6, 2, 3, 33, 11, 33, 4, 99 };
removeDuplicates(arr);
}

private static void removeDuplicates(int[] arr) {
int[] temp = new int[arr.length];
List<Integer> list = new ArrayList<Integer>();
int j=0;
for (int i = 0; i < arr.length; i++) {
if (list.contains(arr[i])) {
} else {
list.add(arr[i]);
temp[j]=arr[i];
j++;
}
}
arr=temp;
//this is only for printing
for(Integer i : arr){
System.out.println(i);
}
}

}

ArrayList is the solution. HashSet can be used too, but AL is faster a bit.

public static void main(String[] args) {
		int[] arr = { 1, 3, 67, 3, 6, 88, 9, 56, 4, 5, 7, 23, 4, 99 };
		removeDuplicatesUsingAL(arr);
//		removeDuplicatesUsingHashSet(arr);
	}

	public static void removeDuplicatesUsingAL(int[] arr) {
		long startTime = System.nanoTime();
		System.out.println("Start time: " + startTime);
		List<Integer> list = new ArrayList<Integer>();
		for (int i = 0; i < arr.length; i++) {
			if (!list.contains(arr[i])) {
				list.add(arr[i]);
			}
		}

		for (Integer i : list) {
			System.out.println("values are: " + i);
		}
		long endTime = System.nanoTime();
		System.out.println("End time: " + endTime);
		System.out.println("total Time is: " + (endTime - startTime));
	}

	public static void removeDuplicatesUsingHashSet(int[] arr) {
		long startTime = System.nanoTime();
		System.out.println("Start time: " + startTime);
		Set hashSet = new HashSet();
		for (int i = 0; i < arr.length; i++) {
			if (!hashSet.contains(arr[i])) {
				hashSet.add(arr[i]);
			}
		}

		Iterator iter = hashSet.iterator();
		while (iter.hasNext()) {
			System.out.println("values are: " + iter.next());
		}
		long endTime = System.nanoTime();
		System.out.println("End time: " + endTime);
		System.out.println("total Time is: " + (endTime - startTime));
	}

using Systems;
using Systems.Collections.Generic;

class sample
{
	public static void Main()
	{
		int[] arr={1,2,3,1,2,3,1,4,5};
		Dictionary<int,int> dict=new Dictionary<int,int>();
		foreach(var a in arr)
		{
			if(!dict.ContainsKey(a))
			dict.Add(a,1);
		}
		foreach(var a in dict)
		{
			Console.Write(a.Key+" ");
		}
		
	}
}

write like this...

Set<T> mySet = new HashSet<T>(Arrays.asList(someArray));