[LeetCode]3sum

最新推荐文章于 2022-01-27 22:44:32 发布

AlwaysCoding

最新推荐文章于 2022-01-27 22:44:32 发布

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分类专栏： leetcode

本文链接：https://blog.youkuaiyun.com/icodingc/article/details/14108095

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本文探讨了在给定整数数组中寻找所有和为特定目标值的三元组的算法实现，通过使用排序和双指针技巧优化搜索效率。

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#include<iostream>
#include<vector>
#include<algorithm>
using namespace std;
class solution{
public:
	vector<vector<int> > threesum(vector<int>& num){
		vector<vector<int> > result;
		if(num.size()<3) return result;
	    sort(num.begin(),num.end());
		const int target=0;

		auto last=num.end();
		for(auto a=num.begin();a<prev(last,2);
			a=upper_bound(a,prev(last,2),*a)){
				for(auto b=next(a);b<prev(last);
					b=upper_bound(b,prev(last),*b)){
						const int c=target-*a-*b;
						if(binary_search(next(b),last,c))
						{
							vector<int> coll;
						    coll.push_back(*a);
							coll.push_back(*b);
							coll.push_back(c);
							result.push_back(coll);
						}

				}
		}
		return result;
	}
};
 void print(vector< vector<int> > & result)  
    {  
        
        for(int i = 0; i < result.size(); i++)  
        {  
            for(int j = 0; j < result[i].size(); j++)  
            {  
                cout<<result[i][j]<<" ";  
            }  
            cout<<endl;  
        }  
  
    }  
int main()
{
	vector<int> a;
	a.push_back(-1);
	a.push_back(0);
	a.push_back(1);
	a.push_back(2);
	a.push_back(-1);
	a.push_back(4);
	solution s;
	s.threesum(a);
	print(s.threesum(a));  
}