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 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 Details

    • AllOne

      public AllOne()

  • Method Details

    • inc

      public void inc(String key)

    • dec

      public void dec(String key)

    • getMaxKey

      public String getMaxKey()

    • getMinKey

      public String getMinKey()