题目描述
算法1
(dfs+剪枝)
C++ 代码
class Solution {
public:
vector<vector<int>> combinationSum2(vector<int>& candidates, int target) {
vector<vector<int>> res;
vector<int>ans;
//排序是为了去重
sort(candidates.begin(), candidates.end());
dfs(res,candidates,target,0,0,ans);
return res;
}
void dfs(vector<vector<int>> &res,vector<int>& candidates, int target,int idx,int sum,vector<int> ans){
if(sum > target) return;
if(sum == target){
res.push_back(ans);
return;
}
for(int i = idx;i < candidates.size();i++){
//发现重复(这重复是指的组间重复)就跳过
if (i > idx && candidates[i] == candidates[i - 1])
continue;
ans.push_back(candidates[i]);
//i+1和组合总数的区别是为了保证组内元素不重复
dfs(res,candidates,target,i+1,sum+candidates[i],ans);
ans.pop_back();
}
}
};