ZOJ3411 Special Special Judge

问题描述：

The norm of a vector v = (v₁, v₂, ... , v_n) is define as norm(v) = |v₁| + |v₂| + ... + |v_n|. And in Problem 0000, there are n cases, the standard output is recorded as a vector x = (x₁, x₂, ... , x_n). The output of a submitted solution is also records as a vector y = (y₁, y₂, ... , y_n). The submitted solution will be accepted if and only if norm(x - y) ≤ m (a given tolerance).

    Knowing that all the output x_i are in range [a, b], an incorrent solution that outputs integer y_i in range [a, b] with equal probability may also get accepted. Given the standard output x_i, you are supposed to calculate the possibility of getting accepted using such solution.

n, m, a, b (1 ≤ n, m ≤ 50, -50 ≤ a < b ≤ 50)

Accepted

3411

Java

380MS

9938K

  
    

   
     
   
     import
   
      java.util.
   
     *
   
     ;

   
     import
   
      java.math.
   
     *
   
     ;


   
     public
   
      
   
     class
   
      Main{
 
   
     public
   
      
   
     static
   
      
   
     void
   
      main(String[] args){
 
   
     int
   
      n,m,a,b,x[]
   
     =
   
     new
   
      
   
     int
   
     [
   
     51
   
     ];
 BigInteger d[][]
   
     =
   
     new
   
      BigInteger[
   
     51
   
     ][
   
     51
   
     ],f1,f2,f3;
 Scanner cin
   
     =
   
     new
   
      Scanner(System.in);
 
   
     while
   
     (cin.hasNext()) {
 n
   
     =
   
     cin.nextInt();
 m
   
     =
   
     cin.nextInt();
 a
   
     =
   
     cin.nextInt();
 b
   
     =
   
     cin.nextInt();
 
   
     //
   
     System.out.println(n+" "+m+" "+a+" "+b);
   
     

   
      
   
     int
   
      i,j,k,t;
 
   
     for
   
     (i
   
     =
   
     1
   
     ;i
   
     <=
   
     n;i
   
     ++
   
     )
 x[i]
   
     =
   
     cin.nextInt();
 
   
     for
   
     (i
   
     =
   
     0
   
     ;i
   
     <=
   
     n;i
   
     ++
   
     )
 
   
     for
   
     (j
   
     =
   
     0
   
     ;j
   
     <=
   
     m;j
   
     ++
   
     )
 d[i][j]
   
     =
   
     BigInteger.ZERO;
 
   
     for
   
     (i
   
     =
   
     a;i
   
     <=
   
     b;i
   
     ++
   
     ){
 t
   
     =
   
     Math.abs(i
   
     -
   
     x[
   
     1
   
     ]);
 
   
     //
   
     System.out.println(t);
   
     

   
      
   
     if
   
     (t
   
     <=
   
     m) {
 d[
   
     1
   
     ][t]
   
     =
   
     d[
   
     1
   
     ][t].add(BigInteger.ONE);
 
   
     //
   
     System.out.println("d[1]["+t+"]="+d[1][t]);
   
     

   
      }
 }
 
 
   
     for
   
     (i
   
     =
   
     2
   
     ;i
   
     <=
   
     n;i
   
     ++
   
     ){
 
   
     for
   
     (j
   
     =
   
     a;j
   
     <=
   
     b;j
   
     ++
   
     ){
 t
   
     =
   
     Math.abs(j
   
     -
   
     x[i]);
 
   
     if
   
     (t
   
     <=
   
     m){
 
   
     for
   
     (k
   
     =
   
     t;k
   
     <=
   
     m;k
   
     ++
   
     ){
 d[i][k]
   
     =
   
     d[i][k].add(d[i
   
     -
   
     1
   
     ][k
   
     -
   
     t]);
 
   
     //
   
     System.out.println("d["+i+"]["+k+"]="+d[i][k]);
   
     

   
      }
 }
 }
 }
 f1
   
     =
   
     BigInteger.ZERO;
 
   
     for
   
     (i
   
     =
   
     0
   
     ;i
   
     <=
   
     m;i
   
     ++
   
     )
 f1
   
     =
   
     f1.add(d[n][i]);
 f2
   
     =
   
     BigInteger.ONE;
 
   
     for
   
     (i
   
     =
   
     1
   
     ;i
   
     <=
   
     n;i
   
     ++
   
     )
 f2
   
     =
   
     f2.multiply(BigInteger.valueOf(b
   
     -
   
     a
   
     +
   
     1
   
     ));
 
   
     //
   
     System.out.println(f1+" "+f2);
   
     

   
      f3
   
     =
   
     f1.gcd(f2);
 f1
   
     =
   
     f1.divide(f3);
 f2
   
     =
   
     f2.divide(f3);
 System.out.println(f1
   
     +
   
     "
   
     /
   
     "
   
     +
   
     f2);
 }
 }
}

   
     /*
   
     
1 1 0 2
1
4 2 2 5
2 3 2 4
4 3 2 5
2 3 2 4

1/1
3/32
7/32

   
     */
  
    

代码的核心部分是Lines 30-40。简单吧，嘻嘻…