Given an int array which might contain duplicates, find if it is a sequence.

Given an int array which might contain duplicates, find if it is a sequence.
Eg. {45,50,47,46,49,48}
is a sequence 45, 46,47,48,49,50
Sorting is an obvious solution. Can this be done in O(n) time and O(1) space

                                            (Or)
Write a method that takes an int array of size m, and returns (True/False) if the array consists of the numbers n...n+m-1, all numbers in that range and only numbers in that range. The array is not guaranteed to be sorted. (For instance, {2,3,4} would return true. {1,3,1} would return false, {1,2,4} would return false.

By working with a[i] % a.length instead of a[i] you reduce the problem to needing to determine that you've got the numbers 0 to a.length - 1.

Approach:
Example array: A = {4, 1, 3, 3, 2}
1. get the min and max.
min=1 and max=4
2. if (max - min) > A.length then "its NOT a sequence".
3. else for each element in A[i] do the following:
a. calculate A[i] - min till A[i]-min=i;
i=0; 4 - 1 = 3, swap A[0] and A[3]
Now we have A = {3, 1, 3, 4, 2}
Again,
i=0; 3 - 1 = 2, now A[0] and A[2] are same so swap A[0] and A[length-1] and put A[length] = infinite.
A = {2, 1, 3, 4, INF}
Again,
i=0; 2 - 1 = 1, swap A[0] and A[1],
A = {1, 2, 3, 4, INF}
i=1; 2 - 1 = 1 (which is same as i)
similarlty for i=2, i=3
finally we have A as,
A = {1, 2, 3, 4, INF}

public static boolean isSequence(int A[])
{
    int min = Integer.MINIMUM;
    int max = Integer.MAXIMUM;
    int len = A.length;
    for(int i=0;i<len;i++)
    {
        if(A[i] < min)
        {
            min = A[i];
        }else if(A[i] > max)
        {
            max = A[i];
        } 
    }
    
    if(max-min > A.length)
        return false;
    
    int i=0;
    while(i<len)
    {
        while(i<len && i != (A[i] - min))
        {
              if(A[A[i] - min] == A[i])
              {
                   A[i] = A[len-1] ;
                   A[len-1] = Integer.MAXIMUM;
                   len = len-1;
              }else
              {
                  int k = A[i] - min;
                  int temp= A[i];
                  A[i] = A[k];
                  A[k] = temp;
              }
        
        }
        
        i++;
  
    }
    
    for(int i=1;i<len;i++)
    {
        if((A[i] - A[i-1]) != -1
        return false;
    }
    
    return true;
}