Codility : MaxProductOfThree

A non-empty zero-indexed 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 zero-indexed 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.

Assume that:

  • 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].

Complexity:

  • expected worst-case time complexity is O(N*log(N));
  • expected worst-case space complexity is O(1), beyond input storage (not counting the storage required for input arguments).

 

def solution(A):
    # write your code in Python 2.7
    A=sorted(A)
    return max(A[0]*A[1]*A[-1],A[-1]*A[-2]*A[-3])
email@djangotutsme.com April 6, 2016, 8:53 a.m.