Problema
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).
Vincoli
1 ≤ a, b ≤ 1,000,000,000
Esempi
Esempio 1
Input:
a = 4
b = 6
Output atteso:
expected = 12Input:
long long a = 4;
long long b = 6;
Output atteso:
long long expected = 12;Input:
long a = 4;
long b = 6;
Output atteso:
long expected = 12;Spiegazione
Multiples of 4: 4, 8, 12…; multiples of 6: 6, 12…; the first common one is 12.
Esempio 2
Input:
a = 7
b = 7
Output atteso:
expected = 7Input:
long long a = 7;
long long b = 7;
Output atteso:
long long expected = 7;Input:
long a = 7;
long b = 7;
Output atteso:
long expected = 7;Spiegazione
A number's LCM with itself is the number: 7.
Come affrontarlo
Prova prima da solo, poi apri un suggerimento alla volta.
Suggerimento 1
Use the relationship between gcd and lcm instead of searching for multiples.
Suggerimento 2
Compute the gcd first, then combine the two numbers carefully.
Suggerimento 3
Divide before multiplying to reduce overflow risk, even with large inputs.
Complessità attesa
O(log min(a, b)) time, O(1) extra space
Riferimenti
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