The following algorithm takes an input array and the output array has duplicate elements removed. What is the Big-O of this algorithm?

Question

void algo(int[] array), int len){
array = sort(array);
int[] newArray = new int[len];
int pos = 0;
for(int x=0;x int elem = array[x];
if(binarySearch(elem, newArray)==-1){
newArray[pos++] = elem;
}
}

a. O(n log n)
b. O(n^2)
c. O(n)
d. O(n!)

Answer 1

a. O(n log n)
The first array is traversed, and then the second array is traversed to find if the element from the first is in the second. Both are of length n so O(n) * O(n) = O(n^2).