Add solution for Challenge 2 by fzzv #635
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Contributor
WalkthroughAdds a complete Go solution file that reads a single line from standard input, reverses it using an exported Changes
Estimated code review effort🎯 1 (Trivial) | ⏱️ ~3 minutes
Possibly related PRs
Pre-merge checks❌ Failed checks (1 warning)
✅ Passed checks (2 passed)
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Comment on lines
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| 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) | ||
|
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| // Print the result | ||
| fmt.Println(output) | ||
| } | ||
| } |
Contributor
There was a problem hiding this comment.
Add error handling for scanner.
The code doesn't check scanner.Err() after the scan operation. If an I/O error occurs, it will be silently ignored.
Apply this diff to add proper error handling:
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)
+ }
}📝 Committable suggestion
‼️ IMPORTANT
Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation. Thoroughly test & benchmark the code to ensure it meets the requirements.
Suggested change
| 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) | |
| } | |
| } | |
| 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) | |
| } | |
| } |
🤖 Prompt for AI Agents
In challenge-2/submissions/fzzv/solution-template.go around lines 9 to 21, the
main function reads input with bufio.NewScanner but does not check scanner.Err()
after scanning; add a check immediately after the Scan block to call
scanner.Err(), and if non-nil, write the error to stderr (or log it) and exit
with a non-zero status so I/O errors are not silently ignored; keep the existing
successful path that prints the reversed string when no error occurred.
Comment on lines
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| func ReverseString(s string) string { | ||
| n := len(s) | ||
| if n <= 1 || n > 1000 { | ||
| return s | ||
| } | ||
|
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| b := []byte(s) | ||
| for i, j := 0, n-1; i <j; i, j = i+1, j-1 { | ||
| b[i], b[j] = b[j], b[i] | ||
| } | ||
| return string(b) | ||
| } |
Contributor
There was a problem hiding this comment.
Byte-level reversal breaks multi-byte UTF-8 characters.
The function reverses the string at the byte level, which corrupts multi-byte UTF-8 characters like emojis or non-ASCII text. For example, "Hello 👋" would become garbled instead of "👋 olleH".
Apply this diff to handle Unicode correctly using runes:
// ReverseString returns the reversed string of s.
func ReverseString(s string) string {
- n := len(s)
- if n <= 1 || n > 1000 {
- return s
- }
-
- b := []byte(s)
- for i, j := 0, n-1; i <j; i, j = i+1, j-1 {
- b[i], b[j] = b[j], b[i]
- }
- return string(b)
+ runes := []rune(s)
+ n := len(runes)
+ if n <= 1 || n > 1000 {
+ return s
+ }
+
+ for i, j := 0, n-1; i < j; i, j = i+1, j-1 {
+ runes[i], runes[j] = runes[j], runes[i]
+ }
+ return string(runes)
}Committable suggestion skipped: line range outside the PR's diff.
🤖 Prompt for AI Agents
In challenge-2/submissions/fzzv/solution-template.go around lines 24 to 35, the
function reverses the string at the byte level which corrupts multi-byte UTF-8
characters; change to operate on runes by converting the input to a []rune, use
its length for the n and the 1000 check, reverse the rune slice in-place (swap
runes[i] and runes[j] while i<j), and return string(runes) so multi-byte Unicode
characters (emojis, non-ASCII) are preserved.
This was referenced Nov 5, 2025
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Challenge 2 Solution
Submitted by: @fzzv
Challenge: Challenge 2
Description
This PR contains my solution for Challenge 2.
Changes
challenge-2/submissions/fzzv/solution-template.goTesting
Thank you for reviewing my submission! 🚀