Leetcode #1324: Print Words Vertically
In this guide, we solve Leetcode #1324 Print Words Vertically in Python and focus on the core idea that makes the solution efficient.
You will see the intuition, the step-by-step method, and a clean Python implementation you can use in interviews.
Problem Statement
Given a string s. Return all the words vertically in the same order in which they appear in s.
Quick Facts
- Difficulty: Medium
- Premium: No
- Tags: Array, String, Simulation
Intuition
We need to scan characters while tracking positions or counts.
A simple state machine keeps the logic precise.
Approach
Iterate through the string once and update the state for each character.
Use a map or array if you need fast lookups.
Steps:
- Iterate through characters.
- Maintain necessary state.
- Build or validate the output.
Example
Input: s = "HOW ARE YOU"
Output: ["HAY","ORO","WEU"]
Explanation: Each word is printed vertically.
"HAY"
"ORO"
"WEU"
Python Solution
class Solution:
def printVertically(self, s: str) -> List[str]:
words = s.split()
n = max(len(w) for w in words)
ans = []
for j in range(n):
t = [w[j] if j < len(w) else ' ' for w in words]
while t[-1] == ' ':
t.pop()
ans.append(''.join(t))
return ans
Complexity
The time complexity is O(n). The space complexity is O(1) to O(n).
Edge Cases and Pitfalls
Watch for boundary values, empty inputs, and duplicate values where applicable. If the problem involves ordering or constraints, confirm the invariant is preserved at every step.
Summary
This Python solution focuses on the essential structure of the problem and keeps the implementation interview-friendly while meeting the constraints.