LeetCode Link: 2785. Sort Vowels in a String
Language: C#
Problem Statement
Given a 0-indexed string s, permute s to get a new string t such that:
All consonants remain in their original places. More formally, if there is an index i with 0 <= i < s.length such that s[i] is a consonant, then t[i] = s[i]. The vowels must be sorted in the nondecreasing order of their ASCII values. More formally, for pairs of indices i, j with 0 <= i < j < s.length such that s[i] and s[j] are vowels, then t[i] must not have a higher ASCII value than t[j]. Return the resulting string.
The vowels are ‘a’, ‘e’, ‘i’, ‘o’, and ‘u’, and they can appear in lowercase or uppercase. Consonants comprise all letters that are not vowels.
Examples
Example 1:
Input: s = “lEetcOde”
Output: “lEOtcede”
Explanation: ‘E’, ‘O’, and ‘e’ are the vowels in s; ‘l’, ‘t’, ‘c’, and ‘d’ are all consonants. The vowels are sorted according to their ASCII values, and the consonants remain in the same places.
Example 2:
Input: s = “lYmpH”
Output: “lYmpH”
Explanation: There are no vowels in s (all characters in s are consonants), so we return “lYmpH”.
Constraints
- 1 <= s.length <= 105
- s consists only of letters of the English alphabet in uppercase and lowercase.
Solution
public class Solution
{
public string SortVowels(string s)
{
char[] vows = ['a','e', 'i', 'o', 'u', 'A', 'E', 'I', 'O', 'U'];
var c = new int[s.Length];
var pos = 0;
for (int i=0; i < s.Length; i++)
{
if (vows.Contains(s[i]))
{
c[pos] = i;
pos++;
}
}
if (pos == 0)
{
return s;
}
var vow = new char[pos];
for (int i=0; i < pos; i++)
{
vow[i] = s[c[i]];
}
Array.Sort(vow);
pos = 0;
var sb = new StringBuilder();
for (int i=0; i < s.Length; i++)
{
if (i == c[pos])
{
sb.Append(vow[pos]);
pos++;
continue;
}
sb.Append(s[i]);
}
return sb.ToString();
}
}
Complexity
Time Complexity: O(N)
Space Complexity: O(N)