Package g1601_1700.s1622_fancy_sequence

Class 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 Detail

      • Fancy

        public Fancy()

    • Method Detail

      • append

        public void append​(int val)

      • addAll

        public void addAll​(int inc)

      • multAll

        public void multAll​(int m)

      • getIndex

        public int getIndex​(int idx)