CF60D.Savior
省选/NOI-
通过率:0%
时间限制:4.00s
内存限制:256MB
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题目描述
Misha decided to help Pasha and Akim be friends again. He had a cunning plan — to destroy all the laughy mushrooms. He knows that the laughy mushrooms can easily burst when they laugh. Mushrooms grow on the lawns. There are a[t] mushrooms on the t-th lawn.
Misha knows that the lawns where the mushrooms grow have a unique ability. A lawn (say, i) can transfer laugh to other lawn (say, j) if there exists an integer (say, b) such, that some permutation of numbers a[i], a[j] and b is a beautiful triple (i ≠ j). A beautiful triple is such three pairwise coprime numbers x, y, z, which satisfy the following condition: _x_2 + _y_2 = _z_2.
Misha wants to know on which minimal number of lawns he should laugh for all the laughy mushrooms to burst.
米沙决定帮助帕沙和阿金重归于好。他有一个狡猾的计划——摧毁所有“爱笑蘑菇”。他知道,当这些蘑菇发笑时,它们很容易爆裂。蘑菇生长在草坪上,第 t 块草坪上有 a[t] 个蘑菇。
米沙知道,长有蘑菇的草坪具有一种独特能力:若存在某个整数 b,使得 a[i]、a[j] 和 b 的某种排列构成一个“优美三元组”(其中 i=j),则第 i 块草坪便可将笑声传递给第 j 块草坪。“优美三元组”是指三个两两互质的正整数 x,y,z,满足如下条件:
x2+y2=z2.
米沙想知道:他至少需要在多少块草坪上发笑,才能使所有爱笑蘑菇全部爆裂?
输入格式
The first line contains one integer n (1 ≤ n ≤ 106) which is the number of lawns. The next line contains n integers a__i which are the number of mushrooms on the i-lawn (1 ≤ a__i ≤ 107). All the numbers are different.
第一行包含一个整数 n(1≤n≤106),表示草坪的数量。
下一行包含 n 个整数 ai,表示第 i 块草坪上的蘑菇数量(1≤ai≤107)。所有数字互不相同。
输出格式
Print a single number — the minimal number of lawns on which Misha should laugh for all the mushrooms to burst.
输出一个整数——米沙需要在上面发笑的最少草坪数量,使得所有蘑菇都爆裂。
输入输出样例
输入#1
1 2
输出#1
1
输入#2
2 1 2
输出#2
2
输入#3
2 3 5
输出#3
1
输入解题思路,AI测评打分。不知道怎么写?