fork download
copy 
  1. program grdeg
  2.  
  3.     integer, allocatable :: A(:,:), B(:,:), ecc(:)
  4.  
  5.     read(*, *) n
  6.     allocate(A(n,n), B(n,n), ecc(n))
  7.  
  8.     call rdmat(A, n)
  9.     call connect(A, n, B)
  10.     ecc = maxval(B, 1)
  11.     irad = minval(ecc, ecc > 0)
  12.     idia = maxval(ecc)
  13.  
  14.     print*, 'radius: ', irad
  15.     print*, 'diameter: ', idia
  16.  
  17. contains
  18.     subroutine prmat(A, n, d)
  19.         character(len=40) ::  fmt
  20.         integer, intent(in) :: n, d
  21.         integer, intent(inout) :: A(n,n)
  22.         write(fmt, '(A,I0,A,I0,A)') '(', n, '(I', d, ':,X))'
  23.         write(*, fmt) ((A(j,i), j=1,n) ,i=1,n)
  24.     end subroutine
  25.  
  26.     subroutine rdmat(A, n)
  27.         integer, intent(inout) :: A(n,n)
  28.         A = 0
  29.         do
  30.             read(*,*, end=1) i,j
  31.             A(i,j) = A(i,j)+1
  32.             A(j,i) = A(j,i)+1
  33.         end do
  34.     1   continue  
  35.     end subroutine
  36.  
  37.     subroutine connect(A, n,  B)
  38.         integer, intent(in) :: A(n,n)
  39.         integer, intent(out):: B(n,n)
  40.         integer:: C(n,n)
  41.         B = 0
  42.         C = A
  43.  
  44.         do i=1,n
  45.             where (B == 0 .and. C > 0) B = i
  46.             C = MATMUL(A,C)
  47.         end do
  48.         do i=1,n
  49.            B(i,i) = 0
  50.         end do
  51.     end subroutine
  52.  
  53.  
  54. end program
  55.  
Success #stdin #stdout 0s 3928KB
comments ()
stdin
copy 
3
1 2
1 3
2 1
stdout
copy 
 radius:            1
 diameter:            2
https://ideone.com/tZSbuB
language:
Fortran (gfortran 8.3)
created:
8 years ago
visibility:
public

Share or Embed source code

Discover > Sphere Engine API

The brand new service which powers Ideone!

Discover > IDE Widget

Widget for compiling and running the source code in a web browser!