Description

Submission

class Solution {
public:
    string reverseOnlyLetters(string s) {
        int n = s.size();
        for(int i = 0, j = n - 1; i < j; ++i, --j) {
            while(i < n && !isalpha(s[i])) ++i;
            while(j >= 0 && !isalpha(s[j])) --j;
            if(i < j) swap(s[i], s[j]);
        }
        return s;
    }
};