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Copy pathLeetCode146.java
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98 lines (85 loc) · 2.58 KB
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package LeetCode;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Map;
import java.util.Scanner;
public class LeetCode146 {
private class Node {
Node next, prev;
int key, value;
Node (){}
Node(int key, int value) {
this.value = value;
this.key = key;
}
}
private Node head, tail;
private Map<Integer, Node> map = new HashMap<>();
private int count, capacity;
private void addNode(Node node) {
Node old = head.next;
head.next = node;
node.prev = head;
node.next = old;
old.prev = node;
}
private void removeNode(Node node) {
Node previous = node.prev;
previous.next = node.next;
node.next.prev = previous;
}
private void moveToHead(Node node) {
removeNode(node);
addNode(node);
}
private Node popTail() {
Node pre = tail.prev;
removeNode(pre);
return pre;
}
public LeetCode146(int capacity) {
this.capacity = capacity;
this.count = 0;
head = new Node();
tail = new Node();
head.next = tail;
tail.prev = head;
}
public int get(int key) {
Node node = map.get(key);
if (node == null) return -1;
moveToHead(node);
return node.value;
}
public void put(int key, int value) {
Node node = map.get(key);
if (node == null) {
if (count == capacity) {
map.remove(popTail().key);
--count;
}
Node fresh = new Node(key, value);
map.put(key, fresh);
addNode(fresh);
count++;
} else {
node.value = value;
moveToHead(node);
}
}
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
LeetCode146 instance = new LeetCode146(Integer.valueOf(scanner.nextLine()));
while (scanner.hasNextLine()) {
String command = scanner.nextLine().trim();
if (command.charAt(0) == 'p') {
int key = Integer.valueOf(command.substring(2, command.lastIndexOf(" ")));
int value = Integer.valueOf(command.substring(command.lastIndexOf(" ")+1));
instance.put(key, value);
}else {
int key = Integer.valueOf(command.substring(2));
System.out.println(instance.get(key));
}
}
}
}