all-oone-data-structure（好）

现在这道题目还只有 9.3%的AC率，难度为Hard
Total Accepted: 9
Total Submissions: 97
Difficulty: Hard

https://leetcode.com/problems/all-oone-data-structure/

class AllOne {

// Hashmap for get Node to operate inc and dec
// LinkNode to maintain order
// HashSet to maintain key with certain value

private class LinkNode {
public int val; // maintain current value
LinkNode small; // maintain link to smaller node
LinkNode big; // maintain link to bigger node
Set<String> keySet; // maintain keys with current value

LinkNode(String key, int v) {
keySet = new HashSet<>();
keySet.add(key);
val = v;
}
}

private LinkNode maxNode;
private LinkNode minNode;
Map<String, LinkNode> hmap;

/** Initialize your data structure here. */
public AllOne() {
hmap = new HashMap<>();
maxNode = null;
minNode = null;
}

/** Inserts a new key <Key> with value 1. Or increments an existing key by 1. */
public void inc(String key) {
LinkNode lknd;

if (hmap.containsKey(key)) {
lknd = hmap.get(key);
lknd.keySet.remove(key);

if (lknd.big != null) {
if (lknd.big.val == lknd.val+1) {
lknd.big.keySet.add(key);
hmap.put(key, lknd.big);
}
else {
LinkNode lbig = new LinkNode(key, lknd.val+1);
lbig.small = lknd;
lbig.big = lknd.big;
lknd.big = lbig;
lbig.big.small = lbig;
hmap.put(key, lbig);
}
}
else {
LinkNode lbig = new LinkNode(key, lknd.val+1);
lbig.small = lknd;
lknd.big = lbig;
maxNode = lbig;
hmap.put(key, lbig);
}

// remove original node if necessary
if (lknd.keySet.isEmpty()) {
// for minNode
if (minNode == lknd) {
minNode = lknd.big;
}
else {
lknd.small.big = lknd.big;
}
// for maxNode
if (maxNode == lknd) {
maxNode = lknd.small;
}
else {
lknd.big.small =lknd.small;
}
}
}
else {
if (minNode == null) {
// all list is null
lknd = new LinkNode(key, 1);
minNode = lknd;
maxNode = lknd;
}
else {
if (minNode.val != 1) {
lknd = new LinkNode(key, 1);
lknd.big = minNode;
minNode.small = lknd;
minNode = lknd;
}
else {
minNode.keySet.add(key);
lknd = minNode;
}
}
hmap.put(key, lknd);
}
}

/** Decrements an existing key by 1. If Key's value is 1, remove it from the data structure. */
public void dec(String key) {
LinkNode lknd;

if (hmap.containsKey(key)) {
lknd = hmap.get(key);
lknd.keySet.remove(key);

if (lknd.val == 1) {
hmap.remove(key);
}
else {
if (lknd.small != null) {
if (lknd.small.val == lknd.val - 1) {
lknd.small.keySet.add(key);
hmap.put(key, lknd.small);
}
else {
LinkNode lsmall = new LinkNode(key, lknd.val - 1);
lsmall.big = lknd;
lsmall.small = lknd.small;
lknd.small = lsmall;
lsmall.small.big = lsmall;
hmap.put(key, lsmall);
}
}
else {
LinkNode lsmall = new LinkNode(key, lknd.val - 1);
lknd.small = lsmall;
lsmall.big = lknd;
minNode = lsmall;
hmap.put(key, lsmall);
}
}

// remove original node if necessary
if (lknd.keySet.isEmpty()) {
// for minNode
if (minNode == lknd) {
minNode = lknd.big;
}
else {
lknd.small.big = lknd.big;
}
// for maxNode
if (maxNode == lknd) {
maxNode = lknd.small;
}
else {
lknd.big.small =lknd.small;
}
}

}
}

/** Returns one of the keys with maximal value. */
public String getMaxKey() {
if (maxNode == null) {
return "";
}
Iterator<String> iter = maxNode.keySet.iterator();
return iter.next();
}

/** Returns one of the keys with Minimal value. */
public String getMinKey() {
if (minNode == null) {
return "";
}
Iterator<String> iter = minNode.keySet.iterator();
return iter.next();
}

public void printAll() {
LinkNode tmp = maxNode;
System.out.println("Start print");
if (tmp != null) {
System.out.printf("Node val: %d\n", tmp.val);
Iterator<String> iter = tmp.keySet.iterator();
while (iter.hasNext()) {
System.out.printf("key: %s,", iter.next());
}
System.out.println();
tmp = tmp.small;
}
if (minNode != null) {
System.out.printf("Min Node val: %d\n", minNode.val);
Iterator<String> iter = minNode.keySet.iterator();
while (iter.hasNext()) {
System.out.printf("key: %s,", iter.next());
}
System.out.println();
}
System.out.println("End print");
}
}

/**
* Your AllOne object will be instantiated and called as such:
* AllOne obj = new AllOne();
* obj.inc(key);
* obj.dec(key);
* String param_3 = obj.getMaxKey();
* String param_4 = obj.getMinKey();
*/