Understand what the interviewer is asking for by using test cases and questions about the problem.
- Established a set (2-3) of test cases to verify their own solution later.
- Established a set (1-2) of edge cases to verify their solution handles complexities.
- Have fully understood the problem and have no clarifying questions.
- Have you verified any Time/Space Constraints for this problem?
Could the input parameter be Null?
Could the input string represent negative numbers?
HAPPY CASE
Input: -5
Output: "-5"
Input: 4
Output: "4"
EDGE CASE
Input: 0
Output: "0"
Match what this problem looks like to known categories of problems, e.g. Linked List or Dynamic Programming, and strategies or patterns in those categories.
Sort
Two pointer solutions (left and right pointer variables)
Storing the elements of the array in a HashMap or a Set
Traversing the array with a sliding window
Plan the solution with appropriate visualizations and pseudocode.
General Idea: Iterate from left to right and multiply the integer by 10 each time to shift the number.
1) Create an array
2) Set a negative flag if input value is negative
3) Iterate through the integer backwards through divide by 10 and modulus method
a) Append element to array
4) Reverse the array and join the elements into a string
5) Return newly created string
⚠️ Common Mistakes
Implement the code to solve the algorithm.
class Solution:
def int_to_string(num: int) -> str:
if num == 0:
return "0"
# Set a negative flag if input value is negative
negative_flag = num < 0
num = abs(num)
# Create an array
arr = []
# Iterate through the integer backwards through divide by 10 and modulus method
while num != 0:
# Append element to array
arr.append(chr(num % 10 + ord('0')))
num = num // 10
# Reverse the array and join the elements into a string
arr.reverse()
return "-" + "".join(arr) if negative_flag else "".join(arr)
Review the code by running specific example(s) and recording values (watchlist) of your code's variables along the way.
Evaluate the performance of your algorithm and state any strong/weak or future potential work.
Assume N represents the number of character in the string.