Check-if-One-String-Swap-Can-Make-Strings-Equal.cpp

class Solution
{
  public:
    bool areAlmostEqual(string s1, string s2)
    {
        int n = s1.size();
        int idx1 = -1, idx2 = -1;
        for (int i = 0; i < n; i++)
            if (s1[i] != s2[i])
            {
                if (idx1 == -1)
                    idx1 = i;
                else if (idx2 == -1)
                    idx2 = i;
                else
                    return false;
            };
        return idx1 == -1 || idx2 != -1 && s1[idx1] == s2[idx2] && s1[idx2] == s2[idx1];
    }
};