def reverse(self, s, start, end):
        i = start
        j = end
        while i < j-1:
            s[i], s[1-j] = s[j-1], s[i]
            i += 1
            j -= 1
dataset/ETHPy150Open algorhythms/LeetCode/186 Reverse Words in a String II.py/Solution.reverse/swapped operands of `-`