Problème
Start with n. If it is even, divide it by 2; if it is odd, multiply it by 3 and add 1. Repeat until the value is 1. Include both the starting value and the final 1 in your answer.
Implement collatz_sequence(n).
Input
n: The positive starting integer.
Output
Return the complete sequence in order.
Contraintes
1 ≤ n ≤ 10,000. Inputs in this range reach 1 under this rule; all sequence values fit a signed 64-bit integer.
Exemples
Entrée :
n = 6
Sortie attendue :
expected = [6, 3, 10, 5, 16, 8, 4, 2, 1]Entrée :
long long n = 6;
Sortie attendue :
std::vector<long long> expected = {6, 3, 10, 5, 16, 8, 4, 2, 1};Entrée :
long n = 6;
Sortie attendue :
long[] expected = new long[] {6, 3, 10, 5, 16, 8, 4, 2, 1};Explication
6 is even, so it becomes 3. Then 3 becomes 10. Continue applying the rule until 1.
Entrée :
n = 1
Sortie attendue :
expected = [1]Entrée :
long long n = 1;
Sortie attendue :
std::vector<long long> expected = {1};Entrée :
long n = 1;
Sortie attendue :
long[] expected = new long[] {1};Explication
The starting value is already 1, so no transformations are needed.
Comment l'aborder
Essayez d'abord seul, puis ouvrez les indices un par un.
Indice 1
The sequence is generated by repeatedly applying one rule based on whether the current number is even or odd.
Indice 2
Keep appending each new value until you reach 1.
Indice 3
Watch out that the starting value itself and the final 1 must both appear in the result.
Complexité attendue
O(k) time, O(k) extra space, where k is the sequence length
Références
Ce défi a été adapté pour CodeUtility. Suivez l'énoncé et les contraintes ci-dessus.