EasyNo. 1880
Check if Word Equals Summation of Two Words — LeetCode 1880 Python Solution
- Pattern
- Hash Map
- Topics
- String
- Reading time
- 2 min
- Source
- leetcode.com
The problem
The letter value of a letter is its position in the alphabet starting from 0 (i.e. 'a' -> 0, 'b' -> 1, 'c' -> 2, etc.).
Example
- Input
- firstWord = "acb", secondWord = "cba", targetWord = "cdb"
- Output
- true
- Explanation
- The numerical value of firstWord is "acb" -> "021" -> 21.
Python solution
class Solution:
def isSumEqual(self, firstWord: str, secondWord: str, targetWord: str) -> bool:
def f(s: str) -> int:
ans, a = 0, ord("a")
for c in map(ord, s):
x = c - a
ans = ans * 10 + x
return ans
return f(firstWord) + f(secondWord) == f(targetWord)Complexity
- Time
- O(L)where L is the sum of the lengths of all strings in the problem
- Space · auxiliary
- O(1)
Pattern: Hash Map
Trade memory for time: remember what you have seen so the second pass never happens. LeetCode 1880. Check if Word Equals Summation of Two Words is filed here because the reference solution below belongs to the algorithm family this hub collects, even though its LeetCode tags point elsewhere.
The hash map guide has the Python template for the pattern and the 709 LeetCode problems that use it.
Related problems
| No. | Problem | Difficulty |
|---|---|---|
| 0006 | Zigzag Conversion | Medium |
| 0008 | String to Integer (atoi) | Medium |
| 0038 | Count and Say | Medium |
| 0058 | Length of Last Word | Easy |
| 0065 | Valid Number | Hard |
| 0068 | Text Justification | Hard |
Frequently asked questions
- How hard is LeetCode 1880. Check if Word Equals Summation of Two Words?
LeetCode 1880. Check if Word Equals Summation of Two Words is rated Easy on LeetCode.
- What is the time complexity of LeetCode 1880. Check if Word Equals Summation of Two Words?
The Python solution on this page runs in O(L), where L is the sum of the lengths of all strings in the problem.
- What is the space complexity of LeetCode 1880. Check if Word Equals Summation of Two Words?
The Python solution on this page uses O(1) auxiliary space.
- What topics does LeetCode 1880. Check if Word Equals Summation of Two Words cover?
LeetCode 1880. Check if Word Equals Summation of Two Words is tagged String on LeetCode.