1622. Fancy Sequence
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 integervalto the end of the sequence.void addAll(inc)Increments all existing values in the sequence by an integerinc.void multAll(m)Multiplies all existing values in the sequence by an integerm.int getIndex(idx)Gets the current value at indexidx(0-indexed) of the sequence modulo109 + 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 <= 1000 <= idx <= 105- At most
105calls total will be made toappend,addAll,multAll, andgetIndex.
GoogleTopics
Hints open one at a time
Hint 1
Use two arrays to save the cumulative multipliers at each time point and cumulative sums adjusted by the current multiplier.
Hint 2
The function getIndex(idx) ask to the current value modulo 10^9+7. Use modular inverse and both arrays to calculate this value.
Loading editor…
1class Fancy:
2
3 def __init__(self):
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5
6 def append(self, val: int) -> None:
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9 def addAll(self, inc: int) -> None:
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12 def multAll(self, m: int) -> None:
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15 def getIndex(self, idx: int) -> int:
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19# Your Fancy object will be instantiated and called as such:
20# obj = Fancy()
21# obj.append(val)
22# obj.addAll(inc)
23# obj.multAll(m)
24# param_4 = obj.getIndex(idx)
Starter codePython 3Spaces: 4
Loading editor…
1class Fancy:
2
3 def __init__(self):
4
5
6 def append(self, val: int) -> None:
7
8
9 def addAll(self, inc: int) -> None:
10
11
12 def multAll(self, m: int) -> None:
13
14
15 def getIndex(self, idx: int) -> int:
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19# Your Fancy object will be instantiated and called as such:
20# obj = Fancy()
21# obj.append(val)
22# obj.addAll(inc)
23# obj.multAll(m)
24# param_4 = obj.getIndex(idx)
Starter codePython 3Spaces: 4
Examples
Input
["Fancy","append","addAll","append","multAll","getIndex","addAll","append","multAll","getIndex","getIndex","getIndex"] [[],[2],[3],[7],[2],[0],[3],[10],[2],[0],[1],[2]]
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