Longest subarray whose elements form a continuous sequence

Question

Given an unsorted array of positive integers, find the length of the longest subarray whose elements when sorted are continuous. Can you think of an O(n) solution?

Examp

Answer 1

here's another way to think of your problem: suppose you have an array composed only of 1s and 0s, you want to find the longest consecutive run of 1s. this can be done in linear time by run-length encoding the 1s (ignore the 0's). in order to transform your original problem into this new run length encoding problem, you compute a new array b[i] = (a[i] < a[i+1]). this doesn't have to be done explicitly, you can just do it implicitly to achieve an algorithm with constant memory requirement and linear complexity.