Package g1601_1700.s1622_fancy_sequence

Class Fancy

  • All Implemented Interfaces:
    
public final class Fancy

    1622 - Fancy Sequence\.

    Hard

    Write an API that generates fancy sequences using the append, addAll, and multAll operations.

    Implement the Fancy class:

    • Fancy() Initializes the object with an empty sequence.

    • void append(val) Appends an integer val to the end of the sequence.

    • void addAll(inc) Increments all existing values in the sequence by an integer inc.

    • void multAll(m) Multiplies all existing values in the sequence by an integer m.

    • int getIndex(idx) Gets the current value at index idx (0-indexed) of the sequence modulo <code>10<sup>9</sup> + 7</code>. If the index is greater or equal than the length of the sequence, return -1.

    Example 1:

    Input "Fancy", "append", "addAll", "append", "multAll", "getIndex", "addAll", "append", "multAll", "getIndex", "getIndex", "getIndex" [ [], 2, 3, 7, 2, 0, 3, 10, 2, 0, 1, 2]

    Output: null, null, null, null, null, 10, null, null, null, 26, 34, 20

    Explanation:

    Fancy fancy = new Fancy();

    fancy.append(2); // fancy sequence: 2

    fancy.addAll(3); // fancy sequence: 2+3 ->5

    fancy.append(7); // fancy sequence: 5, 7

    fancy.multAll(2); // fancy sequence: 5\*2, 7\*2 ->10, 14

    fancy.getIndex(0); // return 10

    fancy.addAll(3); // fancy sequence: 10+3, 14+3 ->13, 17

    fancy.append(10); // fancy sequence: 13, 17, 10

    fancy.multAll(2); // fancy sequence: 13\*2, 17\*2, 10\*2 ->26, 34, 20

    fancy.getIndex(0); // return 26

    fancy.getIndex(1); // return 34

    fancy.getIndex(2); // return 20

    Constraints:

    • 1 &lt;= val, inc, m &lt;= 100

    • <code>0 <= idx <= 10<sup>5</sup></code>

    • At most <code>10<sup>5</sup></code> calls total will be made to append, addAll, multAll, and getIndex.

    • Nested Class Summary

      Nested Classes 
      Modifier and Type Class Description

    • Field Summary

      Fields 
      Modifier and Type Field Description

    • Constructor Summary

      Constructors 
      Constructor Description
      Fancy()

    • Enum Constant Summary

      Enum Constants 
      Enum Constant Description