Package g0401_0500.s0432_all_oone_data_structure

Class AllOne

java.lang.Object
g0401_0500.s0432_all_oone_data_structure.AllOne
public class AllOne extends java.lang.Object
432 - All O`one Data Structure.

Hard

Design a data structure to store the strings’ count with the ability to return the strings with minimum and maximum counts.

Implement the AllOne class:

  • AllOne() Initializes the object of the data structure.
  • inc(String key) Increments the count of the string key by 1. If key does not exist in the data structure, insert it with count 1.
  • dec(String key) Decrements the count of the string key by 1. If the count of key is 0 after the decrement, remove it from the data structure. It is guaranteed that key exists in the data structure before the decrement.
  • getMaxKey() Returns one of the keys with the maximal count. If no element exists, return an empty string "".
  • getMinKey() Returns one of the keys with the minimum count. If no element exists, return an empty string "".

Example 1:

Input

 ["AllOne", "inc", "inc", "getMaxKey", "getMinKey", "inc", "getMaxKey", "getMinKey"]
 [ [], ["hello"], ["hello"], [], [], ["leet"], [], []]

Output: [null, null, null, “hello”, “hello”, null, “hello”, “leet”]

Explanation:

 AllOne allOne = new AllOne();
 allOne.inc("hello");
 allOne.inc("hello");
 allOne.getMaxKey(); // return "hello"
 allOne.getMinKey(); // return "hello"
 allOne.inc("leet");
 allOne.getMaxKey(); // return "hello"
 allOne.getMinKey(); // return "leet"

Constraints:

  • 1 <= key.length <= 10
  • key consists of lowercase English letters.
  • It is guaranteed that for each call to dec, key is existing in the data structure.
  • At most 5 * 104 calls will be made to inc, dec, getMaxKey, and getMinKey.

  • Constructor Summary

    Constructors
    Constructor
    Description
    AllOne()
     

  • Method Summary

    Modifier and Type
    Method
    Description
    void
    dec(java.lang.String key)
     
    java.lang.String
    getMaxKey()
     
    java.lang.String
    getMinKey()
     
    void
    inc(java.lang.String key)
     

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Constructor Details

    • AllOne

      public AllOne()

  • Method Details

    • inc

      public void inc(java.lang.String key)

    • dec

      public void dec(java.lang.String key)

    • getMaxKey

      public java.lang.String getMaxKey()

    • getMinKey

      public java.lang.String getMinKey()