Files
wehub-resource-sync dde272c4b8
i18n - Build Validation / Validate i18n Builds (24) (push) Has been cancelled
CI - Node.js / Lint (24) (push) Has been cancelled
CI - Node.js / Build (24) (push) Has been cancelled
CI - Node.js / Test (24) (push) Has been cancelled
CI - Node.js / Test - Upcoming Changes (24) (push) Has been cancelled
CI - Node.js / Test - i18n (italian, 24) (push) Has been cancelled
CI - Node.js / Test - i18n (portuguese, 24) (push) Has been cancelled
CD - Docker - GHCR Images / Build and Push Images (push) Has been cancelled
chore: import upstream snapshot with attribution
2026-07-13 11:55:53 +08:00

99 lines
2.2 KiB
Markdown

---
id: 698a1a863194f1f4e63f645e
title: "Challenge 207: Smallest Gap"
challengeType: 29
dashedName: challenge-207
---
# --description--
Given a string, return the substring between the two identical characters that have the smallest number of characters between them (smallest gap).
- There will always be at least one pair of matching characters.
- The returned substring should exclude the matching characters.
- If two or more gaps are the same length, return the characters from the first one.
For example, given `"ABCDAC"`, return `"DA"` because:
- Only `"A"` and `"C"` repeat in the string.
- The number of characters between the two `"A"` characters is 3, and between the `"C"` characters is 2.
- So return the string between the two `"C"` characters.
# --hints--
`smallest_gap("ABCDAC")` should return `"DA"`.
```js
({test: () => { runPython(`
from unittest import TestCase
TestCase().assertEqual(smallest_gap("ABCDAC"), "DA")`)
}})
```
`smallest_gap("racecar")` should return `"e"`.
```js
({test: () => { runPython(`
from unittest import TestCase
TestCase().assertEqual(smallest_gap("racecar"), "e")`)
}})
```
`smallest_gap("A{5e^SD*F4i!o#q6e&rkf(po8|we9+kr-2!3}=4")` should return `"#q6e&rkf(p"`.
```js
({test: () => { runPython(`
from unittest import TestCase
TestCase().assertEqual(smallest_gap("A{5e^SD*F4i!o#q6e&rkf(po8|we9+kr-2!3}=4"), "#q6e&rkf(p")`)
}})
```
`smallest_gap("Hello World")` should return `""`.
```js
({test: () => { runPython(`
from unittest import TestCase
TestCase().assertEqual(smallest_gap("Hello World"), "")`)
}})
```
`smallest_gap("The quick brown fox jumps over the lazy dog.")` should return `"fox"`.
```js
({test: () => { runPython(`
from unittest import TestCase
TestCase().assertEqual(smallest_gap("The quick brown fox jumps over the lazy dog."), "fox")`)
}})
```
# --seed--
## --seed-contents--
```py
def smallest_gap(s):
return s
```
# --solutions--
```py
def smallest_gap(s):
min_gap = float("inf")
result = ""
for i in range(len(s)):
for j in range(i + 1, len(s)):
if s[i] == s[j]:
gap = j - i - 1
if gap < min_gap:
min_gap = gap
result = s[i + 1:j]
break
return result
```