40. Combination Sum II

Iterative logic to remove duplicates
class Solution:
    def combinationSum2(self, A: List[int], tar: int) -> List[List[int]]:
        A.sort(reverse=True)
        st=[]
        ans=[]
        n=len(A)
        def dfs(i,x):
            if x==tar:
                ans.append(st[:])
            if x>=tar:
                return
            prev=float('inf')
            for j in range(i,n):
                if A[j]!=prev:#Avoiding duplicate step here
                    st.append(A[j])
                    dfs(j+1,x+A[j])
                    st.pop()
                prev=A[j]

        dfs(0,0)
        return ans