class Solution {
public:
vector<vector<
int> > combinationSum(vector<
int> &candidates,
int target)
{
//sort candidates
int size=candidates.size();
for(
int i=
0;i<size;i++)
for(
int j=i+
1;j<size;j++)
if(candidates[i]>candidates[j])
{
int tmp=candidates[i];
candidates[i]=candidates[j];
candidates[j]=tmp;
}
//dfs
vector<vector<
int>> result;
if(size==
0)
return result;
int v[target/candidates[
0]];
int cdep=
0;
int vdep=
0;
dfs(result,candidates,size,v,cdep,vdep,target);
return result;
}
void dfs(vector<vector<
int>>& result,vector<
int> &candidates,
int& csize,
int* v,
int& cdep,
int& vdep,
int& target)
{
if(target==
0)
{
vector<
int> vals;
for(
int i=
0;i<vdep;i++)
vals.push_back(v[i]);
result.push_back(vals);
return;
}
if(cdep==csize || target<candidates[cdep])
return;
int dup=target/candidates[cdep];
for(
int i=
0;i<=dup;i++)
{
//add to v
for(
int j=
0;j<i;j++) v[vdep+j]=candidates[cdep];
//search next candidate
target=target-i*candidates[cdep];
cdep=cdep+
1;
vdep=vdep+i;
dfs(result,candidates,csize,v,cdep,vdep,target);
vdep=vdep-i;
cdep=cdep-
1;
target=target+i*candidates[cdep];
}
}
};