void combine(LLI &results, LI &set, int parent, int n, int k) {
if (set.size() == k) {
results.push_back(set);
return;
}
for (int i = parent + 1; i <= n; ++i) {
set.push_back(i);
combine(results, set, i, n, k);
set.pop_back();
}
}
void search(TreeNode* root, int k1, int k2, LI &vals) {
if (!root)
return;
int m = root->val;
if (k1 < m)
search(root->left, k1, k2, vals);
if (k1 <= m && m <= k2)
vals.push_back(root->val);
if (m < k2)
search(root->right, k1, k2, vals);
}
void combine(LLI &results, LI &set, LI &candidates, int k, int target) {
int sum = 0;
for (int x : set)
sum += x;
if (sum == target) {
LI sorted = set;
sort(sorted.begin(), sorted.end());
results.push_back(sorted);
return;
}
if (target < sum)
return;
for (int i = k; i < candidates.size(); ++i) {
set.push_back(candidates[i]);
combine(results, set, candidates, i, target);
set.pop_back();
}
}
void fourSum(LLI &res, LI &set, const LI &nums, int lo, int target) {
int sum = 0;
for (const int &x : set)
sum += x;
if (set.size() == 4 && sum == target) {
res.push_back(set);
return;
}
if (4 <= set.size())
return;
for (int i = lo; i < nums.size(); ++i) {
if (i != lo && nums[i] == nums[i - 1])
continue;
set.push_back(nums[i]);
fourSum(res, set, nums, i + 1, target);
set.pop_back();
}
}
void push_back(int val){dt.push_back(val);}