The biggest problem is figuring out exactly what should be legal in the string.

最大的问题是如何明确地指出在字符串中哪些是合法的。

youdao

Again, with strings you need to identify what is legal, and reject any other string.

同样，对于字符串您也要确定哪些是合法的，并拒绝所有其他的字符串。

youdao

Again, with strings you need to identify what is legal, and reject any other string.

同样，对于字符串您也要确定哪些是合法的，并拒绝所有其他的字符串。

youdao