Count shortest distance in string
Last updated: July 22, 2025
Quick Overview
Given a string and two characters, calculate the shortest distance between the two characters in the string. The function should return the minimum number of characters that need to be traversed to go from one character to the other. If either character is not present in the string, return -1.
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July 22, 202534
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3,601 solved
Given a string and two characters, calculate the shortest distance between the two characters in the string. The function should return the minimum number of characters that need to be traversed to go from one character to the other. If either character is not present in the string, return -1.
Coding interviews at Snapchat focus on problem-solving approach as much as the final solution. The interviewer wants to see you break down the problem, consider edge cases, and optimize iteratively. Communication throughout the process is key.
What the Interviewer Expects
- Identify the correct data structure and algorithm for the problem
- Write clean, bug-free code with proper variable naming
- Analyze time and space complexity correctly
- Handle basic edge cases (empty input, single element)
- Communicate your thought process while coding
Key Topics to Cover
How to Approach This
- Clarify input constraints and edge cases before writing code.
- Walk through your approach verbally and confirm with the interviewer before coding.
- Start with a brute force solution, then optimize. Mention time and space complexity.
- Test your solution with examples, including edge cases like empty input or duplicates.
- Consider common patterns: sliding window, two pointers, hash map, BFS/DFS, dynamic programming.
Possible Follow-up Questions
- Can you optimize the space complexity of your solution?
- How would your solution change if the input was sorted?
- What if the input doesn't fit in memory?
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Practice DSA ProblemsSample Answer
Problem Analysis
To determine the shortest distance between two characters in a string, we can utilize a linear scan approach which is efficient given the constraints of the problem. The key observation is that we can...
Approach
- Initialize two variables
last_pos_aandlast_pos_bto -1. These will store the most recent indices of the two characters in the string. - Initialize a variable
min_distanceto infinity. This...
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