Question
A non-empty array A consisting of N integers is given. The product of triplet (P, Q, R) equates to A[P] A[Q] A[R] (0 ≤ P < Q < R < N).
For example, array A such that:
A[0] = -3
A[1] = 1
A[2] = 2
A[3] = -2
A[4] = 5
A[5] = 6
contains the following example triplets:
(0, 1, 2), product is −3 1 2 = −6
(1, 2, 4), product is 1 2 5 = 10
(2, 4, 5), product is 2 5 6 = 60
Your goal is to find the maximal product of any triplet.
Write a function:
def solution(A)
that, given a non-empty array A, returns the value of the maximal product of any triplet.
For example, given array A such that:
A[0] = -3
A[1] = 1
A[2] = 2
A[3] = -2
A[4] = 5
A[5] = 6
the function should return 60, as the product of triplet (2, 4, 5) is maximal.
Write an efficient algorithm for the following assumptions:
N is an integer within the range [3..100,000];
each element of array A is an integer within the range [−1,000..1,000].
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Answer
def solution(A):
A.sort()
p1 = A[0] * A[1] * A[-1]
p2 = A[-3] * A[-2] * A[-1]
return max(p1, p2)using heapq
from heapq import nsmallest, nlargest
def heapq(A):
a, b = nsmallest(2, A)
z, y, x = nlargest(3, A)
return max(a*b*z, x*y*z)