vector<TreeNode *>* recusive(int start,int end)
{
vector<TreeNode *> *vl;
vector<TreeNode *> *vr;
vector<TreeNode *> *v;
TreeNode *root;
v = new vector<TreeNode *>();
if(end < start){
v->push_back(NULL);
return v;
}
for(int i = start; i <= end; ++i){
vl = recusive(start,i-1);
vr = recusive(i+1,end);
int l = vl->size();
int r = vr->size();
for(int j = 0; j < l; ++j)
for(int k = 0; k < r; ++k){
root = new TreeNode(i);
root->left = (*vl)[j];
root->right = (*vr)[k];
v->push_back(root);
}
delete vl;
delete vr;
}
return v;
}
void recusive(int idx, int target, vector<int>& candidates)
{
if(target==0)
{
ret.push_back(vec);
return;
}
if(target<0) return;
for( int i=idx; i<candidates.size(); ++i)
{
int val = candidates[i];
vec.push_back(val);
recusive(i, target-val, candidates);
vec.pop_back();
}
}
vector<TreeNode *> generateTrees(int n) {
vector<TreeNode *> *ret = recusive(1,n);
return *ret;
}
vector<vector<int>> combinationSum(vector<int>& candidates, int target) {
sort( candidates.begin(), candidates.end());
recusive(0, target, candidates);
return ret;
}
