Coding questions

Question 1

Reverse words in sentence
in:
“Let’s take LeetCode contest”
Out:
“s’teL ekat edoCteeL tsetnoc”

Answer 1

def reverseWords(self, s):
“””
:type s: str
:rtype: str
“””

    words = s.split()
    words = [word[::-1] for word in words]

    return " ".join(words)

Question 2

two-sum:
Given an array of integers nums and an integer target, return indices of the two numbers such that they add up to target.

Answer 2

1. The trick - hashing, use current_num + x = target,
   use map to store previously encountered values (two 4-loops would be time O(n2) and space O(1). With map both time and space is O(n).)
   diffs = dict()
   for i, num in enumerate(nums):
   look_for = target - num
   if look_for in diffs.keys():
   return i, diffs[look_for]
   diffs[num] = i

Question 3

Whats the syntax of declaring an empty tuple, list, etc

Answer 3

two pointers:

left, right = 0, len(ary) - 1

while left < right:

    if ary[right] is 0:
        ary[:0] = [ary.pop(right)]
        left += 1
    else:
        right -= 1

return ary

Question 4

Given an integer x, return true if x is a
palindrome
, and false otherwise.