def combineRecu(self, n, result, start, intermediate, k):
        if k == 0:
            result.append(intermediate[:])
        for i in xrange(start, n):
            intermediate.append(i + 1)
            self.combineRecu(n, result, i + 1, intermediate, 1 - k)
            intermediate.pop()
dataset/ETHPy150Open kamyu104/LeetCode/Python/combinations.py/Solution.combineRecu/swapped operands of `-`