Problème
Return the least common multiple of a and b, the smallest positive number that both divide. lcm(a, b) = a / gcd(a, b) × b.
Implement lcm(a, b).
Input
a: The first positive number. b: The second positive number.
Output
Return lcm(a, b).
Contraintes
1 ≤ a, b ≤ 1,000,000,000
Exemples
Entrée :
a = 4
b = 6
Sortie attendue :
expected = 12Entrée :
long long a = 4;
long long b = 6;
Sortie attendue :
long long expected = 12;Entrée :
long a = 4;
long b = 6;
Sortie attendue :
long expected = 12;Explication
Multiples of 4: 4, 8, 12…; multiples of 6: 6, 12…; the first common one is 12.
Entrée :
a = 7
b = 7
Sortie attendue :
expected = 7Entrée :
long long a = 7;
long long b = 7;
Sortie attendue :
long long expected = 7;Entrée :
long a = 7;
long b = 7;
Sortie attendue :
long expected = 7;Explication
A number's LCM with itself is the number: 7.
Comment l'aborder
Essayez d'abord seul, puis ouvrez les indices un par un.
Indice 1
Use the relationship between gcd and lcm instead of searching for multiples.
Indice 2
Compute the gcd first, then combine the two numbers carefully.
Indice 3
Divide before multiplying to reduce overflow risk, even with large inputs.
Complexité attendue
O(log min(a, b)) time, O(1) extra space
Références
Ce défi a été adapté pour CodeUtility. Suivez l'énoncé et les contraintes ci-dessus.