leetcode 460 LFU缓存
class Node implements Comparable<Node>{ public int key; public int value; public int lastTime; public int fre; public Node(int key,int value,int lastTime){ this.key=key; this.value=value; this.lastTime = lastTime; this.fre=1; } @Override public int compareTo(Node o) { if(this.fre!=o.fre){ //System.out.println(this.key+"++++fre:"+this.fre); //System.out.println(o.key+"+++++fre"+o.fre); //System.out.println(Integer.compare(o.fre,this.fre)); return Integer.compare(this.fre,o.fre); } //System.out.println(this.key+"---"+this.value); //System.out.println(o.key+"----"+o.value); //System.out.println(-Integer.compare(this.lastTime,o.lastTime)); return Integer.compare(this.lastTime,o.lastTime); } public void setValue(int value,int lastTime) { this.value=value; this.lastTime=lastTime; this.fre++; } public int getValue(int lastTime) { this.lastTime=lastTime; this.fre++; return value; } @Override public boolean equals(Object o) { if (this == o) return true; if (o == null || getClass() != o.getClass()) return false; Node node = (Node) o; return key == node.key; } @Override public int hashCode() { return Objects.hash(key, value); } } class LFUCache { public int capacity; public int time; public HashMap<Integer,Node> values; public TreeSet<Node> keys; public LFUCache(int capacity) { time=0; this.capacity=capacity; values = new HashMap<Integer, Node>(); keys = new TreeSet<Node>(); } public int get(int key) { if(capacity==0) return -1; if(values.containsKey(key)){ Node oldN = values.get(key); keys.remove(oldN); int ans = oldN.getValue(++time); keys.add(oldN); return ans; } else return -1; } public void put(int key, int value) { if(capacity==0) return; if(values.containsKey(key)){ Node oldN = values.get(key); keys.remove(oldN); oldN.setValue(value,++time); keys.add(oldN); }else{ if(values.size()==this.capacity) { Node n = values.get(keys.first().key); values.remove(n.key); keys.remove(n); } Node s = new Node(key,value,++time); values.put(key,s); keys.add(s); } } }