In this post, we are going to solve the Combination Sum II Leetcode Solution problem of Leetcode. This Leetcode problem is done in many programming languages like C++, Java, and Python.
Problem
Given a collection of candidate numbers (candidates) and a target number (target), find all unique combinations in candidates where the candidate numbers sum to target.
Each number in candidates may only be used once in the combination.
Note: The solution set must not contain duplicate combinations.
Example 1:
Input: candidates = [10,1,2,7,6,1,5], target = 8 Output: [ [1,1,6], [1,2,5], [1,7], [2,6] ]
Example 2:
Input: candidates = [2,5,2,1,2], target = 5 Output: [ [1,2,2], [5] ]
Constraints:
1 <= candidates.length <= 1001 <= candidates[i] <= 501 <= target <= 30
Now, let’s see the leetcode solution of Combination Sum II Leetcode Solution.
Combination Sum II Leetcode Solution in Python
class Solution:
def combinationSum2(self, candidates: List[int], target: int) -> List[List[int]]:
ans = []
def dfs(s: int, target: int, path: List[int]) -> None:
if target < 0:
return
if target == 0:
ans.append(path.copy())
return
for i in range(s, len(candidates)):
if i > s and candidates[i] == candidates[i - 1]:
continue
path.append(candidates[i])
dfs(i + 1, target - candidates[i], path)
path.pop()
candidates.sort()
dfs(0, target, [])
return ans
Combination Sum II Leetcode Solution in CPP
class Solution {
public:
vector<vector<int>> combinationSum2(vector<int>& candidates, int target) {
vector<vector<int>> ans;
sort(begin(candidates), end(candidates));
dfs(candidates, 0, target, {}, ans);
return ans;
}
private:
void dfs(const vector<int>& A, int s, int target, vector<int>&& path,
vector<vector<int>>& ans) {
if (target < 0)
return;
if (target == 0) {
ans.push_back(path);
return;
}
for (int i = s; i < A.size(); ++i) {
if (i > s && A[i] == A[i - 1])
continue;
path.push_back(A[i]);
dfs(A, i + 1, target - A[i], move(path), ans);
path.pop_back();
}
}
};
Combination Sum II Leetcode Solution in Java
class Solution {
public List<List<Integer>> combinationSum2(int[] candidates, int target) {
List<List<Integer>> ans = new ArrayList<>();
Arrays.sort(candidates);
dfs(0, candidates, target, new ArrayList<>(), ans);
return ans;
}
private void dfs(int s, int[] candidates, int target, List<Integer> path,
List<List<Integer>> ans) {
if (target < 0)
return;
if (target == 0) {
ans.add(new ArrayList<>(path));
return;
}
for (int i = s; i < candidates.length; ++i) {
if (i > s && candidates[i] == candidates[i - 1])
continue;
path.add(candidates[i]);
dfs(i + 1, candidates, target - candidates[i], path, ans);
path.remove(path.size() - 1);
}
}
}
Note: This problem Combination Sum II is generated by Leetcode but the solution is provided by Chase2learn This tutorial is only for Educational and Learning purposes.
