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### by Sumit Chourasia | May 06, 2020 | Category :coding | Tags : leetcodeडेटा-संरचनाstringआसानalgorithm

#### Reverse Only Letters - मिनी टीवी

Given a string S, return the "reversed" string where all characters that are not a letter stay in the same place, and all letters reverse their positions.

Example 1:

``````Input: "ab-cd"

Output: "dc-ba"``````

Example 2:

``````Input: "a-bC-dEf-ghIj"

Output: "j-Ih-gfE-dCba"``````

Example 3:

``````Input: "Test1ng-Leet=code-Q!"

Output: "Qedo1ct-eeLg=ntse-T!"``````

Note:

``````S.length <= 100

33 <= S[i].ASCIIcode <= 122

S doesn't contain \ or "``````

Solution:

``````using System;
using System.Collections.Generic;
using System.Text;

{
{
public void execute()
{
var res = ReverseOnlyLetters("a-bC-dEf-ghIj");
}

public string ReverseOnlyLetters(string S)
{
char[] str = new char[S.Length];
for (int i = 0, j = S.Length-1; i < S.Length;)
{
if (IsLetter(S[i]) && IsLetter(S[j]))
{
str[i] = S[j];
i++;
j--;
}
else if (!IsLetter(S[i]))
{
str[i] = S[i];
i++;
}
else if (!IsLetter(S[j]))
{
j--;
}
}

return new string(str);
}

private bool IsLetter(char v)
{
return (v >= 97 && v <= 122) || (v >= 65 && v <= 90);
}
}
}
``````

Time Complexity: O(n)

Space Complexity: O(n)

Contributed By: Sumit Chourasia
Contributed By: Sumit Chourasia
Contributed By: Sumit Chourasia
Contributed By: Sumit Chourasia