组合总和

def solve():
    def combinationSum(____):
        result = []
        def backtrack(____):
            if total == target:
                result.append(____)
                return
            if total > target:
                return
            for i in range(start, len(____)):
                path.append(____)
                backtrack(____)
                path.pop()
        backtrack(____, [], ____)
        return result
    print(combinationSum(____))