CareerCup

static public void LongSequence(int[] sequence)
        {
            if (sequence == null || sequence.Length == 0) return;

            Array.Sort(sequence);

            int[] longSeq = null;
            List<int> currentSeq = new List<int>();

            currentSeq.Add(sequence[0]);
            int lastValue = sequence[0];

            for (int i = 1; i < sequence.Length; i++)
            {
                // Is the sequence intact?
                if (lastValue + 1 == sequence[i])
                {
                    currentSeq.Add(sequence[i]);
                }
                else
                {
                    if (longSeq == null || currentSeq.Count > longSeq.Length)
                    {
                        longSeq = currentSeq.ToArray<int>();
                    }

                    currentSeq = new List<int>();
                    currentSeq.Add(sequence[i]);
                }

                lastValue = sequence[i];
            }

            if (longSeq == null || currentSeq.Count > longSeq.Length)
            {
                longSeq = currentSeq.ToArray<int>();
            }
        }

Sort the array and get the sequence!

public class LongSequenceTest {

    public static ArrayList<Integer> LongSequence(Integer... sequence) {
        if (sequence == null || sequence.length == 0)
            return null;

        List<Integer> seqList =  new ArrayList<Integer>(Arrays.asList(sequence));
        Collections.sort(seqList);

        List<Integer> currentSeq = new ArrayList<Integer>();
        List<Integer> retSeq = new ArrayList<Integer>();

        currentSeq.add(seqList.get(0));
        int lastValue = seqList.get(0);
        int longSeq = 0;

        for(int i=1; i < seqList.size(); i++){

            if(lastValue+1 == seqList.get(i)){
                currentSeq.add(seqList.get(i));
                lastValue++;
            } else {
                if(longSeq == 0 || currentSeq.size() > longSeq){
                    longSeq = currentSeq.size();
                    retSeq = currentSeq;
                }
                lastValue = seqList.get(i);
                currentSeq = new ArrayList<Integer>();
                currentSeq.add(seqList.get(i));
            }
        }

        if (longSeq == 0 || currentSeq.size() > longSeq){
            retSeq = currentSeq;
        }

        return (ArrayList<Integer>) retSeq;
    }

    public static void main(String arg[]) {
        ArrayList<Integer> ret = LongSequence(7, 2, 3, 5, 6, 9);

        for(Integer i : ret) {
            System.out.print(i + " ");
        }
    }
}

if space complexity is not the issue ,u can use Hashset . First insert all the element then for each element search its next or previous if anyone present .If any one present delete both from the HashSet and increase the counter accordingly and search for next element .For each new element make count=0,also make track of max count .complexity O(n) both in space and time

Another approach is: We can construct an un-directed graph where nodes are the array elements and there is an edge between two nodes iff their values differ with one. Then we can run the DFS and choose the longest connected component. Complexity is O(V + E).

Insert by direct hashing, then

getLongestSeq(i){
if(i.hasNext)
if(i.noPrev)
store i;
i.count++;
else
getCurrentI
currentI.count++;
getLongestSeq(i.next)
else
find next elem , recurssively run till null

Find the longest sequence in the array.

array = {1, 4, 3, 2, 5, 7, 8, 22}
Answer = 1, 2, 3, 4, 5

What? What does this mean?
Why isn't the whole array the answer?
Longest (sub)sequence of any sequence is the whole sequence.

#include<stdio.h>
#include<stdlib.h>

void sort_array(int arr[], int n)
{
  int i, j, temp;
 
  for (i = 0 ; i < ( n - 1 ); i++)
  {
    for (j = 0 ; j <( n - i - 1); j++)
    {
      if (arr[j] > arr[j+1])
      {
        /* Swapping */
 
        temp  = arr[j];
        arr[j]   = arr[j+1];
        arr[j+1] = temp;
      }
    }
  }
}

int main()
{   
	int i;
	int arr[] = {1,4, 3, 2, 45, 7, 48, 66} ;
	sort_array(arr,7);
	printf("%d ",arr[0]);
	for(i=1;i<sizeof(arr)/sizeof(int);i++)
	{
		if( (arr[i] - arr[i-1]) == 1)
			printf("%d ",arr[i]);
		else
			break;
	}

	 return 0;

}