Subsets
Given a set of distinct integers, S, return all possible subsets.
Note:
- Elements in a subset must be in non-descending order.
- The solution set must not contain duplicate subsets.
For example,
If S = [1,2,3]
, a solution is:
[ [3], [1], [2], [1,2,3], [1,3], [2,3], [1,2], [] ]
class Solution {
public:
vector<vector<int> > subsets(vector<int> &S) {
vector<vector<int> > result;
//sort s
for(int i=0;i<S.size();i++)
for(int j=i+1;j<S.size();j++)
{
if(S[i]>S[j])
{
int tmp=S[i];
S[i]=S[j];
S[j]=tmp;
}
}
vector<int> v;
for(int i=0;i<S.size();i++) v.push_back(0);
gen(result,v,S,0,0,S.size());
return result;
}
void gen(vector<vector<int> >& result,vector<int>& v,vector<int> &S,int dep,int index,int size)
{
vector<int> vnew;
for(int i=0;i<dep;i++)
vnew.push_back(v[i]);
result.push_back(vnew);
for(int i=index;i<size;i++)
{
v[dep]=S[i];
gen(result,v,S,dep+1,i+1,size);
}
}
};
public:
vector<vector<int> > subsets(vector<int> &S) {
vector<vector<int> > result;
//sort s
for(int i=0;i<S.size();i++)
for(int j=i+1;j<S.size();j++)
{
if(S[i]>S[j])
{
int tmp=S[i];
S[i]=S[j];
S[j]=tmp;
}
}
vector<int> v;
for(int i=0;i<S.size();i++) v.push_back(0);
gen(result,v,S,0,0,S.size());
return result;
}
void gen(vector<vector<int> >& result,vector<int>& v,vector<int> &S,int dep,int index,int size)
{
vector<int> vnew;
for(int i=0;i<dep;i++)
vnew.push_back(v[i]);
result.push_back(vnew);
for(int i=index;i<size;i++)
{
v[dep]=S[i];
gen(result,v,S,dep+1,i+1,size);
}
}
};