Problema
Each move removes two coins from one pile and one coin from the other. Either orientation is allowed. You may never remove more coins than remain. Determine whether both piles can end at zero.
Implement coin_piles(left, right).
Input
left: The number of coins in the left pile.
right: The number of coins in the right pile.
Output
Return true if the piles can both be emptied; otherwise return false.
Restricciones
0 ≤ left, right ≤ 1,000,000,000. Two empty piles are already a successful result.
Ejemplos
Entrada:
left = 4
right = 2
Salida esperada:
expected = TrueEntrada:
long long left = 4;
long long right = 2;
Salida esperada:
bool expected = true;Entrada:
long left = 4;
long right = 2;
Salida esperada:
bool expected = true;Explicación
Remove (2, 1) twice: (4, 2) → (2, 1) → (0, 0).
Entrada:
left = 4
right = 1
Salida esperada:
expected = FalseEntrada:
long long left = 4;
long long right = 1;
Salida esperada:
bool expected = false;Entrada:
long left = 4;
long right = 1;
Salida esperada:
bool expected = false;Explicación
The only possible first move leaves (2, 0), after which no move can empty the left pile.
Cómo abordarlo
Inténtalo primero por tu cuenta y luego abre las pistas una a una.
Pista 1
Each move removes exactly three coins total, so the overall coin count must fit that pattern.
Pista 2
Neither pile can be reduced below zero, so one pile cannot exceed what the other can support.
Pista 3
Check both the total amount and the difference between piles.
Complejidad esperada
O(1) time, O(1) extra space
Referencias
Este reto está adaptado para CodeUtility. Sigue el enunciado y las restricciones indicadas arriba.