some more solves

contests/6contest/3.cpp

@@ -0,0 +1,26 @@
+#include <iostream>
+#include <vector>
+#include <functional>
+
+
+template <typename It, typename F>
+void myapply(It first, It last, F f) {
+    for (It it = first; it != last; ++it) {
+        f(*it);
+    }
+
+    return;
+}
+
+template <typename It, typename Pred>
+std::vector<std::reference_wrapper<typename std::iterator_traits<It>::value_type>> myfilter2(It first, It last, Pred f) {
+    std::vector<std::reference_wrapper<typename std::iterator_traits<It>::value_type>> result;
+
+    for (It it = first; it != last; ++it) {
+        if (f(*it)) {
+            result.push_back(std::ref(*it));
+        }
+    }
+
+    return result;
+}

contests/6contest/4.cpp

@@ -0,0 +1,16 @@
+#include <set>
+
+template <typename It1, typename It2>
+It2 myremove(It1 first1, It1 last1, It2 first2, It2 last2) {
+    std::set to_remove(first1, last1);
+    It2 result = first2;
+
+    for (It2 it = first2; it != last2; ++it) {
+        if (to_remove.find(std::distance(first2, it)) == to_remove.end()) {
+            std::iter_swap(result, it);
+            ++result;
+        }
+    }
+
+    return result;
+}