Problema
Sort the values into ascending order. For an odd number of values, take the middle one. For an even number, take the arithmetic mean of the two middle values. This challenge accepts only nonempty lists.
Implement median_number(numbers).
Input
numbers: The nonempty list of values.
Output
Return the median as a number; it may end in .5.
Restricciones
1 ≤ list length ≤ 100,000. Each value is an integer between −1,000,000,000 and 1,000,000,000.
Ejemplos
Entrada:
numbers = [2, 8, 4, 10]
Salida esperada:
expected = 6.0Entrada:
std::vector<long long> numbers = {2, 8, 4, 10};
Salida esperada:
double expected = 6.0;Entrada:
long[] numbers = new long[] {2, 8, 4, 10};
Salida esperada:
double expected = 6.0;Explicación
Sorted order is 2, 4, 8, 10. The middle pair averages to (4 + 8) / 2 = 6.
Entrada:
numbers = [9, 1, 4]
Salida esperada:
expected = 4.0Entrada:
std::vector<long long> numbers = {9, 1, 4};
Salida esperada:
double expected = 4.0;Entrada:
long[] numbers = new long[] {9, 1, 4};
Salida esperada:
double expected = 4.0;Explicación
Sorted order is 1, 4, 9, whose middle value is 4.
Cómo abordarlo
Inténtalo primero por tu cuenta y luego abre las pistas una a una.
Pista 1
The median depends on sorted order, so the positions in the sorted list are what matter.
Pista 2
After sorting, use the middle element for odd length, or combine the two middle elements for even length.
Pista 3
Be careful to preserve halves when averaging two middle values, since the answer may end in .5.
Complejidad esperada
O(n log n) time, O(n) extra space
Referencias
Este reto está adaptado para CodeUtility. Sigue el enunciado y las restricciones indicadas arriba.