https://leetcode.com/problems/combination-sum-ii/
Given a collection of candidate numbers (candidates) and a target number (target), find all unique combinations in candidates where the candidate numbers sums to target.
Each number in candidates may only be used once in the combination.
Note:
- All numbers (including
target) will be positive integers. - The solution set must not contain duplicate combinations.
Example 1:
Input: candidates =[10,1,2,7,6,1,5], target =8, A solution set is: [ [1, 7], [1, 2, 5], [2, 6], [1, 1, 6] ]
Example 2:
Input: candidates = [2,5,2,1,2], target = 5, A solution set is: [ [1,2,2], [5] ]
代码：
class Solution {
public:
vector<vector<int>> combinationSum2(vector<int>& candidates, int target) {
int n = candidates.size();
sort(candidates.begin(), candidates.end());
set<vector<int> > ans;
vector<int> out;
vector<int> vis(n, 0);
dfs(candidates, out, ans, target, 0, vis);
return vector<vector<int>>(ans.begin(), ans.end());
}
void dfs(vector<int> &candidates, vector<int> &out, set<vector<int> > &ans, int key, int st, vector<int> &vis) {
if(key < 0) return ;
else if(key == 0) {
ans.insert(out);
return;
}
for(int i = st; i < candidates.size(); i ++) {
if(vis[i] == 0) {
vis[i] = 1;
out.push_back(candidates[i]);
dfs(candidates, out, ans, key - candidates[i], i, vis);
vis[i] = 0;
out.pop_back();
}
}
}
};