Create Solution.js

Author: 07subhadip

solution/0400-0499/0432.All O`one Data Structure/Solution.js

@@ -0,0 +1,98 @@
+class Node {
+    constructor(key = '', cnt = 0) {
+        this.prev = null;
+        this.next = null;
+        this.cnt = cnt;
+        this.keys = new Set([key]);
+    }
+
+    insert(node) {
+        node.prev = this;
+        node.next = this.next;
+        this.next.prev = node;
+        this.next = node;
+        return node;
+    }
+
+    remove() {
+        this.prev.next = this.next;
+        this.next.prev = this.prev;
+    }
+}
+
+var AllOne = function() {
+    this.root = new Node();
+    this.root.next = this.root;
+    this.root.prev = this.root;
+    this.nodes = {};
+};
+
+AllOne.prototype.inc = function(key) {
+    const root = this.root;
+    const nodes = this.nodes;
+
+    if (!nodes[key]) {
+        if (root.next === root || root.next.cnt > 1) {
+            nodes[key] = root.insert(new Node(key, 1));
+        } else {
+            root.next.keys.add(key);
+            nodes[key] = root.next;
+        }
+    } else {
+        const curr = nodes[key];
+        const next = curr.next;
+
+        if (next === root || next.cnt > curr.cnt + 1) {
+            nodes[key] = curr.insert(new Node(key, curr.cnt + 1));
+        } else {
+            next.keys.add(key);
+            nodes[key] = next;
+        }
+
+        curr.keys.delete(key);
+        if (curr.keys.size === 0) {
+            curr.remove();
+        }
+    }
+};
+
+AllOne.prototype.dec = function(key) {
+    const root = this.root;
+    const nodes = this.nodes;
+    const curr = nodes[key];
+
+    if (curr.cnt === 1) {
+        delete nodes[key];
+    } else {
+        const prev = curr.prev;
+
+        if (prev === root || prev.cnt < curr.cnt - 1) {
+            nodes[key] = prev.insert(new Node(key, curr.cnt - 1));
+        } else {
+            prev.keys.add(key);
+            nodes[key] = prev;
+        }
+    }
+
+    curr.keys.delete(key);
+    if (curr.keys.size === 0) {
+        curr.remove();
+    }
+};
+
+AllOne.prototype.getMaxKey = function() {
+    return this.root.prev === this.root ? '' : Array.from(this.root.prev.keys)[0];
+};
+
+AllOne.prototype.getMinKey = function() {
+    return this.root.next === this.root ? '' : Array.from(this.root.next.keys)[0];
+};
+
+/** 
+ * Your AllOne object will be instantiated and called as such:
+ * var obj = new AllOne()
+ * obj.inc(key)
+ * obj.dec(key)
+ * var param_3 = obj.getMaxKey()
+ * var param_4 = obj.getMinKey()
+ */