"Noi Question Bank" 9269:big string Super Strings

Portal: http://noi.openjudge.cn/ch0207/9269/

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9269:big String Super Strings

Total time limit: 10000ms single test point time limit: 1000ms memory limit: 131072kB

Describe

Fish in countless Oi competitions after the prison, realize a truth, often the easier the topic, the deeper the trap. As a result, fish created this topic.

Fish first gives two short strings of a= ' 4567 ' (4 characters), b= ' 123 ' (3 characters). Do the following repeatedly to get a long string of C.

(1) C=b+a (example: a= ' 4567 ', b= ' 123 ' c=b+a= ' 1234567 ')

(2) A=b b=c (above example a= ' 123 ' b= ' 1234567 ')

Please program to find the nth character of this long string.

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Input

The first line contains an integer n (1<=n<=10^9)

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Output

A single line that contains a character that represents the nth character of the long string.

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Sample input

9

Sample output

2

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Let's look at the length change of a,b,c:

It can be found that the composition of this string is only a few characters 1,2,3,4,5,6,7,

And 4,5,6,7 only belong to ' 4567 ', and the only one is ' 123 ',

Then, but when the number of operations is singular, the end of the string "C" must be ' 4567 ' "Length 4"

But when the number of operations is even, the end of the string "C" must be ' 123 ' "Length 3"

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Ideas:

You can use recursion to find the character that you are looking for in 123 or 4567 of the first, you can find the output.

Code:

1  ProgramChaojizifuchuan;2 var3 N,tochange,tcd:longint;4//-----------------------------------------------------------------------------5 functionNeed (T1:longint): longint;//Several steps are required6 var7 Sum,xh,sum2,su:longint;8 begin9xh:=2; //Two steps are required by defaultTensum:=7; xh-1the string length of the step Onesum2:=Ten; //string length of XH step A    whileSum2<t1 Do//When the string length of the XH step is less than T1 -   begin -Inc (XH); //on the increase of one step thesu:=sum2; //Backup sum2 -sum2:=sum+sum2; //Increase sum2 -SUM:=SU; sum=sum2 at the previous step -   End; +   ift1<=7  Thenxh:=1; //if T1 is less than or equal to 7 only one step is required -tochange:=sum2; //Tochange is used to record the string length "global variable" of XH step at this time +Tcd:=sum; TCD is used to record this time xh-1The string length of the step "global variable" AExit (XH); //back to XH step at End; -//----------------------------------------------------------------------------- - procedureprintf (T2:char); - begin -Writeln (T2); //Output -Halt //terminating the main program in End; -//----------------------------------------------------------------------------- to proceduretry (len:longint); + var - Bu,total,last:longint; the c:string; * begin $   iflen<=7  Then begin//less than or equal to 7 o'clockPanax Notoginsengc:='1234567'; - printf (C[len]); the                      End +   Else begin//greater than 7 o'clock ABu:=need (len); //the number of steps required theTotal:=tochange; //string length when recording bu step +tochange:=0; //Restore Tochange -             ifOdd (BU) Thenlast:=4  $                   Elselast:=3; If the number of steps required is a singular '4567' At the end, if the even is '123' End $             ifLen>=total-last Then begin//if the last segment of the string -                                                 iflast=4  Thenc:='4567' -                                                    Elsec:='123'; //last record is the length of the final paragraph . theprintf (C[len-total+last]); //Output -                                             EndWuyi             Else begin theDec (BU); //this seems to erase Qaq . -TOTAL:=TCD; //Previous step length Wutcd:=0; //Restore TCD -Try (len-total);//continue try that lastend to Len segment "whose length is Len minus the length of the previous step" About                    End; $         End; -  - End; -//----------------------------------------------------------------------------- A begin +READLN (n); //Read in theTry (n); //Try - End.

Happy Mid-Autumn Festival Qaq----in 2016.9.15

"Noi Question Bank" 9269:big string Super Strings