Lonely Integer Given an array of integers, where all elements but one occur twice, find the unique element. Example a=[1,2,3,4,3,2,1]a = [1, 2, 3, 4, 3, 2, 1]a=[1,2,3,4,3,2,1] The unique element is 4. Function Description Complete the lonelyinteger function in the editor below. lonelyinteger has the following parameter(s): int a[n]: an array of integers Returns int: the element that occurs only ..