LeetCode OJ——Subsets

http://oj.leetcode.com/problems/subsets/

计算一个集合的子集，使用vector<vector<int> >，使用了进制的思想。

#include<algorithm>

#include<vector>

#include<iostream>

#include<cmath>

using namespace std;

class Solution {

private:

	void myoutput(vector<int> &input)

		 {

			 for(int i=0;i<input.size();i++)

				 cout<<input[i]<<" ";

		 }

    int mypow(int i)

	{

		if(i ==0 )

			return 1;

		int ret = 1;

		while(i--)

			ret *= 2;

		return ret;

	}

public:

	vector<vector<int> > subsets(vector<int> &S) {

		// Note: The Solution object is instantiated only once and is reused by each test case.

		sort(S.begin(),S.end());

        //myoutput(S);

		int sum = mypow(S.size());

		//cout<<sum<<endl;

	    //cout<<sum<<"sum"<<endl;

		vector<vector<int> > result;

		result.clear();

		sum--;

		vector<int> tep_result;

		for(int i = sum;i>0;i--)

		{

			tep_result.clear();

			int _sum = i;

			int digit = 0;

			while(_sum!=0)

			{

				if(_sum%2==1)

					tep_result.push_back(S[digit]);

				digit++;

				_sum /= 2;

			}

			result.push_back(tep_result);

			//二维vector的使用方式，是直接添加一维的

		}

		tep_result.clear();

		result.push_back(tep_result);

		//for(int j = 0;j<result.size();j++)

		//{

		//cout<<"this:";

		//myoutput(result[j]);

		//cout<<endl;

		//}

		return result;

	}

};

#include<iostream>

#include"solu.h"

using namespace std;

int main()

{

	Solution *so = new Solution;

	vector<int> input;

	input.clear();

	/*input.push_back(3);

	input.push_back(1);

	input.push_back(2);

	input.push_back(5);*/

	so->subsets(input);

	//cout<<"ok"<<endl;

	if(so!=NULL)

		delete so;

	so = NULL;

	return 0;

}