Add solution for Challenge 2 by Johrespi #648
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WalkthroughA new Go solution file is added to the Challenge 2 submissions directory. It implements an exported Changes
Estimated code review effort🎯 2 (Simple) | ⏱️ ~8 minutes
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Actionable comments posted: 1
🧹 Nitpick comments (1)
challenge-2/submissions/Johrespi/solution-template.go (1)
9-21: Consider checking for scanner errors.The scanner could encounter an error while reading input. While the current implementation may be acceptable for this challenge, it's good practice to check
scanner.Err()after the scan loop.Example:
func main() { // Read input from standard input scanner := bufio.NewScanner(os.Stdin) if scanner.Scan() { input := scanner.Text() // Call the ReverseString function output := ReverseString(input) // Print the result fmt.Println(output) } + if err := scanner.Err(); err != nil { + fmt.Fprintf(os.Stderr, "Error reading input: %v\n", err) + os.Exit(1) + } }
| func ReverseString(s string) string { | ||
| // TODO: Implement the function | ||
| var output string | ||
| for c := len(s) - 1; c >= 0; c-- { | ||
| output += string(s[c]) | ||
| } | ||
| return output | ||
| } |
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Fix critical Unicode bug: byte indexing breaks multi-byte UTF-8 characters.
The current implementation treats the string as a byte array by indexing with s[c]. This corrupts multi-byte UTF-8 characters like emojis, accented letters, or non-ASCII text. For example, reversing "café" or "Hello 👋" will produce garbled output.
Additionally, string concatenation in a loop has O(n²) time complexity because strings are immutable in Go.
Apply this diff to fix both issues:
-// ReverseString returns the reversed string of s.
func ReverseString(s string) string {
- // TODO: Implement the function
- var output string
- for c := len(s) - 1; c >= 0; c-- {
- output += string(s[c])
- }
- return output
+ runes := []rune(s)
+ for i, j := 0, len(runes)-1; i < j; i, j = i+1, j-1 {
+ runes[i], runes[j] = runes[j], runes[i]
+ }
+ return string(runes)
}This solution:
- Converts the string to a rune slice to properly handle Unicode characters
- Uses in-place swapping for O(n) time complexity
- Removes the obsolete TODO comment
Committable suggestion skipped: line range outside the PR's diff.
🤖 Prompt for AI Agents
In challenge-2/submissions/Johrespi/solution-template.go around lines 24 to 31,
the current implementation indexes the string by bytes and concatenates in a
loop, which corrupts multi-byte UTF-8 characters and is O(n²); fix by converting
the input string to a rune slice, perform in-place swapping of runes
(two-pointer swap from ends toward center) to reverse in O(n) time, then return
a new string created from the rune slice, and remove the obsolete TODO comment.
2 participants
Challenge 2 Solution
Submitted by: @Johrespi
Challenge: Challenge 2
Description
This PR contains my solution for Challenge 2.
Changes
challenge-2/submissions/Johrespi/solution-template.goTesting
Thank you for reviewing my submission! 🚀