Maximum Pairwise Product

问题描述

Given a sequence of non-negative integers a0,…,an−1, find the maximum pairwise product, that is, the largest integer that can be obtained by multiplying two different elements from the sequence (or, more formally, max0≤i≠j≤n−1aiaj). Different elements here mean ai and ajwith i≠j (it can be the case that ai=aj).

输入格式

The first line of the input contains an integer n. The next line contains nnon-negative integers a0,…,an−1 (separated by spaces).

限制条件

2≤n≤2⋅105; 0≤a0,…,an−1≤105.

输出格式

Output a single number — the maximum pairwise product.

样例 1

输入：

3

1 2 3

输出：

6

样例 2

输入：

10

7 5 14 2 8 8 10 1 2 3

输出：

140

样例 3 

输入：

5

4 6 2 6 1

输出：

36

n = int(input())
a = [int(x) for x in input().split()]
assert(len(a) == n)

curMax=sndMax=0
for idx in range(0, n):
    if curMax < a[idx]:
        sndMax = curMax
        curMax = a[idx]
    elif sndMax < a[idx]:
        sndMax=a[idx]
print(curMax*sndMax)