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 Summary

Constructors

Constructor and Description
Fancy()

Method Summary

Modifier and Type	Method and Description
void	addAll(int inc)
void	append(int val)
int	getIndex(int idx)
void	multAll(int m)

Methods inherited from class java.lang.Object

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

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)