Add C++ implementation

Signed-off-by: begeekmyfriend <begeekmyfriend@gmail.com>

Author: begeekmyfriend

146_lru_cache/lru_cache.cc

@@ -19,7 +19,7 @@ class LRUCache {
             return -1;
         }
 
-        int value = ht_[key]->second;
+        int value = (*ht_[key]).second;
         if (li_.front().first != key) {
             li_.erase(ht_[key]);
             li_.push_front(make_pair(key, value));

460_lfu_cache/Makefile

@@ -1,2 +1,3 @@
 all:
-	g++ -O1 -std=c++11 -o test lfu_cache.cc
+	gcc -O1 -o test lfu_cache.c
+	#g++ -O1 -std=c++11 -o test lfu_cache.cc