题解 | #牛群喂食#

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<>>
     */
    vector<vector<int> >ve;
    vector<int>pa;
    void dfs(vector<int>& candidates, int target) {
        if (target < 0) return;
        if (target == 0) {
            int s[51] = {0};
            for (int i = 0; i < pa.size(); i++) s[pa[i]]++;
            int add = 0;
            for (int i = 0; i < ve.size(); i++) {
                int temp[51] = {0};
                for (int j = 0; j < ve[i].size(); j++) {
                    temp[ve[i][j]]++;
                }
                int flag = 0;
                for (int k = 0; k <= 50; k++) {
                    if (temp[k] != s[k]) {
                        flag = 1;
                        break;
                    }
                }
                if(!flag) {
                    add = 1;
                    break;
                }
            }
            if (!add) {
                    ve.push_back(pa);
                    return;
                }
        }
        for (int i = 0; i < candidates.size(); i++) {
            pa.push_back(candidates[i]);
            target -= candidates[i];
            dfs(candidates, target);
            target += pa.back();
            pa.pop_back();
        }
    }
    vector<vector<int> > cowCombinationSum(vector<int>& candidates, int target) {
        dfs(candidates, target);
        return ve;
    }
};