“In an array with integers between 1 and 1,000,000 one value is in the array twice. How do you deter

[XXL1990]

I have been asked the following by one of my tutors
“In an array with integers between 1 and 1,000,000 one value is in the array twice. How do you determine which one?”

How would i go about implementing the above in either java or c#?

Thanks in advance