compilation error fixed

Author: aadarshkt

dynamic_programming/longest_increasing_subsequence_(nlogn).cpp

@@ -3,7 +3,7 @@
 // tested on : https://cses.fi/problemset/task/1145/
 
 #include <iostream>
-
+#include <set>
 using namespace std;
 int LIS(int arr[], int n) {
     set<int> active;  // The current built LIS.
@@ -29,10 +29,8 @@ int LIS(int arr[], int n) {
 }
 int main(int argc, char const* argv[]) {
     int n;
-    cout << "Enter size of array: ";
     cin >> n;
     int a[n];
-    cout << "Enter array elements: ";
     for (int i = 0; i < n; ++i) {
         cin >> a[i];
     }