Java face question

A recent interview has encountered a pen question.

1, the number of the tail 0 of the factorial result of 1000.

Solution: Calculates the number of 5 that can be decomposed
The idea is that 1000! = 1000*999*...*1, and 5*2= 10, so long as all the number from 1 to 1000 decomposition into (2,5) combination, you can know the number of mantissa 0. At the same time, it is clear that the number of 2 is more than the number of 5, so only need to focus on the number of decomposition of 5.

 PackageCom.tk.demos; Public classTest { Public Static voidMain (string[] args) {intc =NewTest (). Test (1000);    System.out.println (c); }     Public intTestintTotal ) {        intCount = 0;  for(inti = 5; I <= total; i++) {            intTMP =i;  while(tmp% 5 = = 0) {Count++; TMP= TMP/5; }        }        returncount; }}

Additional solutions found on the Web:

Statistical calculation by classification

There are:

625 in Multiples: 1 (625*16)

Multiples of 125:8-1 = 7 (minus 625)

Multiples of 25:40-8 = 32 (remove the 7+1 above)

Multiples of 5:200-40 = 160 (Remove the 32+7+1 above)

Total: 1*4+7*3+32*2+160=249 of 0

2, assuming that similar to the "ABA", "AAB" string equality, writing methods to judge any given two sets of strings equal.

 PackageCom.tk.demos; Public classTest { Public Static voidMain (string[] args) {BooleanTest =NewTest (). Strequals ("AB", "ABA");    SYSTEM.OUT.PRINTLN (test); }     Public Booleanstrequals (String strone, String strtwo) {if(Strone = =NULL&& Strtwo = =NULL) {            return true; }        if(Strone = =NULL|| Strtwo = =NULL) {            return false; }        if(Strone.length ()! =strtwo.length ()) {            return false; }        returnsort (strone). Equals (sort (strtwo)); }     Publicstring Sort (string strin) {Char[] S1 =Strin.tochararray ();  for(inti = 0; I < S1.length; i++) {             for(intj = 0; J < I J + +) {                if(S1[i] < S1[j]) {                    Chartemp =S1[i]; S1[i]=S1[j]; S1[J]=temp; }            }        }        returnstring.valueof (S1); }}

3. If you use the return statement in a try statement block, will the finally statement block also execute?

Answer: Will

The answer to this question is very simple, just inadvertently read an article on the Internet, very interesting.

What is the output of the following code? the answer is: 2, not 3 .

classTest { Public intaaa () {intx = 1; Try {            return++x; } Catch(Exception e) {}finally {            ++x; }        returnx; }     Public Static voidMain (string[] args) {Test T=NewTest (); inty =t.aaa ();    System.out.println (y); }}

Specific analysis can look at this article you really understand the return of try{return}finally{}?

Java face question