39. Combination Sum
class Solution {
public:
vector<vector<int>> ans;
void dfs(vector<int>& candidates, vector<int>& V, int now, int target) {
if(target == 0) {
ans.push_back(V);
return ;
}
for(int ii = now; ii < candidates.size() && target >= candidates[ii]; ii++) {
V.push_back(candidates[ii]);
dfs(candidates, V, ii, target - candidates[ii]);
V.pop_back();
}
}
vector<vector<int>> combinationSum(vector<int>& candidates, int target) {
sort(candidates.begin(), candidates.end());
vector<int> V;
dfs(candidates, V, 0, target);
return ans;
}
};
class Solution {
public:
vector<vector<int>> ans;
void dfs(vector<int>& candidates, vector<int> V, int sum, int now, int target) {
while(sum + candidates[now] <= target) {
sum += candidates[now];
V.push_back(candidates[now]);
if(sum == target) {
ans.push_back(V);
return ;
}
for(int ii = now + 1; ii < candidates.size(); ii++) {
dfs(candidates, V, sum, ii, target);
}
}
}
vector<vector<int>> combinationSum(vector<int>& candidates, int target) {
vector<int> V;
for(int ii = 0; ii < candidates.size(); ii++) {
dfs(candidates, V, 0, ii, target);
}
return ans;
}
};