205. Isomorphic Strings

[jzhangnu]

var isIsomorphic = function(s, t) {
    var x={}, y={};

    for(var i=0; i<s.length; i++){
        if(!x[s[i]] && !y[t[i]]){
            x[s[i]] = t[i];
            y[t[i]] = s[i];
        }else if(x[s[i]] !== t[i] || y[t[i]] !== s[i]){
            return false;
        }
    }
    return true;
};