Create 432-all-oone-data-structure.js

Author: everthis

432-all-oone-data-structure.js

@@ -0,0 +1,77 @@
+/**
+ * Initialize your data structure here.
+ */
+const AllOne = function() {
+  this.map = new Map()
+}
+
+/**
+ * Inserts a new key <Key> with value 1. Or increments an existing key by 1.
+ * @param {string} key
+ * @return {void}
+ */
+AllOne.prototype.inc = function(key) {
+  let curCount
+  if (this.map.has(key)) {
+    curCount = this.map.get(key) + 1
+  } else {
+    curCount = 1
+  }
+  this.map.set(key, curCount)
+}
+
+/**
+ * Decrements an existing key by 1. If Key's value is 1, remove it from the data structure.
+ * @param {string} key
+ * @return {void}
+ */
+AllOne.prototype.dec = function(key) {
+  if (this.map.has(key)) {
+    if (this.map.get(key) > 1) {
+      this.map.set(key, this.map.get(key) - 1)
+    } else this.map.delete(key)
+  } else {
+    return
+  }
+}
+
+/**
+ * Returns one of the keys with maximal value.
+ * @return {string}
+ */
+AllOne.prototype.getMaxKey = function() {
+  let max = -Infinity,
+    maxStr = ''
+  for (let k of this.map) {
+    if (k[1] > max) {
+      max = k[1]
+      maxStr = k[0]
+    }
+  }
+  return maxStr
+}
+
+/**
+ * Returns one of the keys with Minimal value.
+ * @return {string}
+ */
+AllOne.prototype.getMinKey = function() {
+  let min = Infinity,
+    minStr = ''
+  for (let k of this.map) {
+    if (k[1] < min) {
+      min = k[1]
+      minStr = k[0]
+    }
+  }
+  return minStr
+}
+
+/**
+ * Your AllOne object will be instantiated and called as such:
+ * var obj = Object.create(AllOne).createNew()
+ * obj.inc(key)
+ * obj.dec(key)
+ * var param_3 = obj.getMaxKey()
+ * var param_4 = obj.getMinKey()
+ */