JS clean solution 68ms
\nvar areAlmostEqual = function(s1, s2) {\n    if(s1 === s2) return true;\n    let res="";\n    \n    for(let i=0;i<s1.length;i++)\n        if(s1[i] !== s2[i]) 
```\nvar areAlmostEqual = function(s1, s2) {\n    if(s1 === s2) return true;\n    let res="";\n    \n    for(let i=0;i<s1.length;i++)\n        if(s1[i] !== s2[i]) res += s1[i]+s2[i];        \n    \n    return res.length === 4 && res[0]===res[3] && res[1] === res[2];\n};\n```
['JavaScript']