class Solution:
    def combinationSum(self, candidates: list[int], target: int) -> list[list[int]]:
        candidates.sort()
        rlt = []
        def dfs(cur, l, cur_num):
            if cur == 0:
                rlt.append(l)
            for candidate in candidates:
                if cur - candidate >= 0 and candidate >= cur_num:
                    dfs(cur - candidate, l + [candidate], candidate)
        dfs(target, [], candidates[0])
        return rlt


sol = Solution()
print(sol.combinationSum([2,3,6,7], 7))