hdu1133 Buy the Ticket (Carrante number of applications +java large number)

Title Link: http://acm.hdu.edu.cn/showproblem.php?pid=1133

Test instructions

Movie tickets, 50 bucks a piece.

There are just 50 pieces in the hand of M-man, there is just 100 in the hand, and the ticket office starts to have no money. Ask, how many kinds of queues, can let everyone buy tickets.

(If the ticket office does not have 50 pieces of change, the person holding 100 will not be able to buy the ticket)

Analysis

Obviously, when M<n, there are 0 ways of arranging.

When the m>=n:

With 0, representing only 50 people in the hand, 1, representing only 100 pieces of the hand.

0110100 This condition does not satisfy the condition (cannot be bought by the third person)

We flip the person that includes the third person and his previous (1->0, 0->1)

1000100 appeared this sequence;

0110100 has 4 0, 3 1 1000100 5 0, 2 1

Every unsatisfied case corresponds to a condition in which such a sequence cannot be satisfied.

C (M+1,m+n);

We calculate the formula is: the legal arrangement means = all arrangement way-illegal arrangement way

So there's F (N) = (-) *m!  *n! ;

And then simplify it again;

F (N) = (m+n)! * (m-n+1)/(m+1);

Because the data is too large, so use the Java large number to solve

Code

Import Java.util.*;import Java.math.biginteger;public class main{public    static void Main (string[] args) {            int a , b;            Scanner in=new Scanner (system.in);            int cnt=0;            while (In.hasnext ()) {                cnt++;                A=in.nextint ();                B=in.nextint ();                BigInteger Ans=biginteger.one;                if (a==0&&b==0) break;                if (a<b) Ans=biginteger.zero;                else {for                    (int i=1;i<=a+b;i++) {                        ans=ans.multiply (biginteger.valueof (i));                    }                    int mpl= (a-b+1);                    int dvd= (a+1);                    Ans=ans.multiply (biginteger.valueof (MPL));                    Ans=ans.divide (biginteger.valueof (DVD));                }                System.out.println ("Test #" +cnt+ ":");                System.out.println (ANS);}}        

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hdu1133 Buy the Ticket (Carrante number of applications +java large number)