954. 二倍数对数组

版权声明：孔庆鑫 https://blog.csdn.net/kongqingxin12/article/details/84930515

954. 二倍数对数组
解题思路：根据题目要求，数组A中包含正数、负数和0，所以我们将数组A进行分割排序，然后求解

class Solution {
public:
	bool canReorderDoubled(vector<int>& A) {
		sort(A.begin(), A.end());
		vector<int>positive_number, negative_number;
		int zero_nums = 0;
		for (auto i = A.begin(); i != A.end(); i++)
		{
			if (*i > 0)
			{
				positive_number.push_back(*i);
			}
			else if (*i < 0)
			{
				negative_number.push_back(*i);
			}
			else if (*i == 0)
			{
				zero_nums++;
			}
		}
		if (positive_number.size() % 2 != 0 || negative_number.size() % 2 != 0 || zero_nums % 2 != 0)
			return false;
		if (check(positive_number, 1) && check(negative_number, 0))
			return true;
		return false;
	}
	bool check(vector<int>nums,bool sign)
	{
		while (nums.size()!=0)
		{
			int te = 0;
			if (sign)
				te = *nums.begin() * 2;
			else
			{
				if (*nums.begin() % 2 == 0)
					te = *nums.begin() / 2;
				else
					return false;
			}
			auto pos = find(nums.begin(), nums.end(), te);
			if (pos != nums.end())
				nums.erase(pos), nums.erase(nums.begin());
			else
				return false;
		}
		return true;
	}
};