no need to update the iterator in cachemap[key]

Author: applewjg

LRUCache.h

@@ -26,7 +26,6 @@ class LRUCache{
     int get(int key){
         if (cachemap.find(key) != cachemap.end()) {
             cachelist.splice(cachelist.begin(), cachelist, cachemap[key]);
-            cachemap[key] = cachelist.begin();
             return cachemap[key]->value;
         }
         else {
@@ -37,7 +36,6 @@ class LRUCache{
     void set(int key, int value) {
         if (cachemap.find(key) != cachemap.end()) {
             cachelist.splice(cachelist.begin(), cachelist, cachemap[key]);
-            cachemap[key] = cachelist.begin();
             cachemap[key]->value = value;
         }
         else {