#P15621. [ICPC 2022 Jakarta R] Doubled GCD

[ICPC 2022 Jakarta R] Doubled GCD

题目描述

There are NN cards in a deck, numbered from 11 to NN, where card ii has a positive integer AiA_i written on it.

You are to perform N1N - 1 moves with the cards. In each move, you select two cards of your choice from the deck. Let xx and yy be the integers written on the selected cards, respectively. Remove both selected cards, and insert a new card into the deck with 2gcd(x,y)2 \cdot \gcd(x, y) written on it, where gcd(x,y)\gcd(x, y) is the greatest common divisor of xx and yy. Note that with this one move, there will be one fewer card in the deck (as you remove two cards and insert one new card).

After all N1N - 1 moves have been performed, there will be exactly one card remaining. Your goal is to maximize the integer written on the last card; output this integer.

输入格式

Input begins with an integer NN (2N1000002 \leq N \leq 100\,000) representing the number of cards. The next line contains NN integers AiA_i (1Ai1061 \leq A_i \leq 10^6) representing the number written on card ii.

输出格式

Output an integer in a single line representing the maximum possible integer written on the last card.

3
2 4 6
8
3
3 5 7
2
4
9 9 9 9
36
5
10 100 1000 10000 100000
160

提示

Explanation for the sample input/output #1

To get the maximum possible integer on the last card, you have to select card 11 and card 33 on the first move with x=2x = 2 and y=6y = 6. Remove both selected cards, and insert a new card with 2gcd(2,6)=42 \cdot \gcd(2, 6) = 4 written on it. For the second move, there are two cards remaining with an integer 44 written on each card. Select those cards with x=4x = 4 and y=4y = 4. Remove both selected cards, and insert a new card with 2gcd(4,4)=82 \cdot \gcd(4, 4) = 8 written on it. The last card has an integer 88 written on it, and it is the maximum possible integer in this example.

Explanation for the sample input/output #2

Regardless of your choice in each move, the answer will always be 22.