Package g1101_1200.s1146_snapshot_array

Class SnapshotArray

  • All Implemented Interfaces:
    
public final class SnapshotArray

    1146 - Snapshot Array\.

    Medium

    Implement a SnapshotArray that supports the following interface:

    • SnapshotArray(int length) initializes an array-like data structure with the given length. Initially, each element equals 0.

    • void set(index, val) sets the element at the given index to be equal to val.

    • int snap() takes a snapshot of the array and returns the snap_id: the total number of times we called snap() minus 1.

    • int get(index, snap_id) returns the value at the given index, at the time we took the snapshot with the given snap_id

    Example 1:

    Input: "SnapshotArray","set","snap","set","get" [3,0,5,[],0,6,0,0]

    Output: null,null,0,null,5

    Explanation:

    SnapshotArray snapshotArr = new SnapshotArray(3); // set the length to be 3 snapshotArr.set(0,5); // Set array0 = 5 snapshotArr.snap(); // Take a snapshot, return snap_id = 0 snapshotArr.set(0,6); snapshotArr.get(0,0); // Get the value of array0 with snap_id = 0, return 5

    Constraints:

    • 1 <= length <= 50000

    • At most 50000 calls will be made to set, snap, and get.

    • 0 <= index < length

    • 0 <= snap_id < (the total number of times we call snap())

    • 0 <= val <= 10^9

    • Nested Class Summary

      Nested Classes 
      Modifier and Type Class Description

    • Field Summary

      Fields 
      Modifier and Type Field Description

    • Enum Constant Summary

      Enum Constants 
      Enum Constant Description

    • Method Summary

      Modifier and Type Method Description
      final Unit set(Integer index, Integer val)
      final Integer snap()
      final Integer get(Integer index, Integer snapId)

      • Methods inherited from class java.lang.Object

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