Lette Code Two Sum

最新推荐文章于 2022-01-26 16:54:20 发布

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最新推荐文章于 2022-01-26 16:54:20 发布

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分类专栏：数据结构与算法 C++

本文链接：https://blog.youkuaiyun.com/baidu_19340981/article/details/39005073

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本文介绍了一种解决两数之和问题的算法实现方法，使用C++编程语言通过二分查找的方式找到目标值，并利用排序和遍历技巧确定两个数的位置。

</pre><pre name="code" class="cpp">

class Solution
{
public:
	vector<int> twoSum(vector<int> &numbers, int target) {

		int len = numbers.size();
		vector<int>midArry(numbers.begin(),numbers.end());
		sort(midArry.begin(),midArry.end());

		for (int i = 0; i < len-1;++i)
		{
			if(binSearch(midArry,target-midArry[i],i+1,len-1))  // if(binary_search(numbers.begin(),numbers.end(),target-midArry[i]))
			{

				vector<int> res = findPos(numbers,midArry[i],target-midArry[i]);
				for (int i = 0; i < 2; ++i)
				{
					cout<<res[i]<<" ";
				}
				cout<<endl;
				return res;
			}

		}
	}

	bool binSearch(vector<int> &midArry, int num,int low,int high)   <span style="color:#ff0000;">// 可以直接用STL里的binary_search</span>
	{
		int mid = (low+high)/2;
		if (midArry[mid] == num)
			return true;
		else if (low > high)
			return false;
		if (midArry[mid] >= num && binSearch(midArry,num,low,mid-1 ))
			return true;
		else if ((midArry[mid] < num && binSearch(midArry,num,mid+1,high )))
			return true;
		return false;
	}

	vector<int> findPos(vector<int> &numbers,int n,int m)   <span style="color:#ff0000;">// 别返回函数里创建的引用</span>
	{ 
		vector<int> res;
		for (int i = 0; i<numbers.size()&&res.size()<2;++i)
		{
			if (numbers[i] == n || numbers[i] == m)
				res.push_back(i+1);
		}

		return res;
	}

};