Package g1601_1700.s1622_fancy_sequence

Class Fancy

java.lang.Object
g1601_1700.s1622_fancy_sequence.Fancy
public class Fancy extends Object
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 109 + 7. 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 <= val, inc, m <= 100
  • 0 <= idx <= 105
  • At most 105 calls total will be made to append, addAll, multAll, and getIndex.

  • Constructor Details

    • Fancy

      public Fancy()

  • Method Details

    • append

      public void append(int val)

    • addAll

      public void addAll(int inc)

    • multAll

      public void multAll(int m)

    • getIndex

      public int getIndex(int idx)