☆打卡算法☆LeetCode 39、组合总和 算法解析

示例 1：
输入: candidates = [2,3,6,7], target = 7
输出: [[7],[2,2,3]]

示例 2：
输入: candidates = [2,3,5], target = 8
输出: [[2,2,2,2],[2,3,3],[3,5]]

public class Solution {
    public IList<IList<int>> CombinationSum(int[] candidates, int target) 
    {
        List<IList<int>> result=new List<IList<int>>();
        List<int> current=new List<int>();       
        dfs(candidates,target,result,current,0);
        return result;
    }
    public void dfs(int[] candidates, int target, List<IList<int>> result, List<int> current,int begin)
    {
            if (target == 0)
            {
                result.Add(new List<int>(current));
                return;
            }
            if (target < 0) return;
            for (int i = begin; i < candidates.Length; i++)
            {
                current.Add(candidates[i]);
                target -= candidates[i];
                
                dfs(candidates, target, result, current,i);
                target += candidates[i];
                current.Remove(candidates[i]);
            }
    }
}