Maximum Product of Two Numbers

You are given an array of integers. Your task is to compute the maximum product of any two distinct elements in the array. If the array contains fewer than two elements, the answer is 0.

Formally, if the input array is \(A = [a_1, a_2, \dots, a_n]\), you are to find \[ \max_{1 \le i < j \le n} (a_i \times a_j), \] with the convention that if \(n < 2\) then the answer is 0.

Examples:

• For nums = [3, 4, 5, 2], the maximum product is 20.
• For nums = [1, 5, 3, 2, 4], the maximum product is 20.
• For nums = [1, 1, 1, 1], the maximum product is 1.
• For nums = [9] or an empty array, the answer is 0.

inputFormat

The input is given via standard input. The first line contains an integer n which is the number of elements in the array. The second line contains n space-separated integers representing the elements of the array.

outputFormat

Output a single integer on standard output, which is the maximum product of any two distinct elements in the array. If the array contains fewer than two elements, output 0.

## sample

4
3 4 5 2

20

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