By "missing" I assume that the numbers are consecutive and we are at least provided with a range.
Suppose for the sake of example, the range is 100,000 to 400,000 with 203,148 being the missing number. They come to us shuffled up, and let us suppose we are taking them from the hard drive instead of an array, one by one. Now if the range is known, there is an interesting property of XOR that you can use. A variable initialized to 0 can be XOR'd with every element in the range, and then XOR'd with all the provided numbers. It will then become the missing number. Ruby example (again, assume numbers coming from hard drive or other source, one at a time, and not array in memory): [image: Inline image 1] -- You received this message because you are subscribed to the Google Groups "Algorithm Geeks" group. To post to this group, send email to algogeeks@googlegroups.com. To unsubscribe from this group, send email to algogeeks+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/algogeeks?hl=en.
<<image.png>>
