_3063.java

packagecom.fishercoder.solutions.fourththousand;

importcom.fishercoder.common.classes.ListNode;
importjava.util.HashMap;
importjava.util.Map;

publicclass_3063 {
publicstaticclassSolution1 {
publicListNodefrequenciesOfElements(ListNodehead) {
Map<Integer, Integer> map = newHashMap<>();
while (head != null) {
map.put(head.val, map.getOrDefault(head.val, 0) + 1);
head = head.next;
 }
ListNodepre = newListNode(-1);
ListNodetmp = pre;
for (Map.Entry<Integer, Integer> entry : map.entrySet()) {
tmp.next = newListNode(entry.getValue());
tmp = tmp.next;
 }
returnpre.next;
 }
 }
}