Edits #include directives

My computer doesn't seem to have the stdc++.h, so I tried changing it to the two headers really used.

Math/Prime_Factorization/primefactorization.cpp

@@ -1,4 +1,5 @@
-#include <bits/stdc++.h>
+#include <iostream>
+#include <vector>
 #include <algorithm>
 using namespace std;