C++ 排序+深度优先搜索 题解 | #牛群喂食#

#include <vector>
class Solution {
public:
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     * 
     * @param candidates int整型vector 
     * @param target int整型 
     * @return int整型vector<vector<>>
     */
    
    set<vector<int>> s_v;
    vector<vector<int> > ans;
    void dfs(vector<int>& candidates, int target, vector<int> v, int sum)
    {
        int len = candidates.size();

        if(sum==target)
        {
            sort(v.begin(),v.end());
            if(s_v.count(v)==0)
            {
                s_v.emplace(v);
                ans.emplace_back(v);
            }
            return;
        }

        if(sum > target)
            return;

        for(int i=0; i<len; ++i)
        {
            v.emplace_back(candidates[i]);
            dfs(candidates, target, v, sum + candidates[i]);
            v.pop_back();
        }
           

        return;
    }

    vector<vector<int> > cowCombinationSum(vector<int>& candidates, int target) {
        // write code here

        sort(candidates.begin(), candidates.end());
        vector<int> v;
        dfs(candidates, target, v, 0);
        return ans;
    }
};