Another update from ingydotnet^djgoku

Task/Permutations/Fortran/permutations-2.f

@@ -1,41 +1,27 @@
-      program nptest
-      integer n,i,a
-      logical nextp
-      external nextp
-      parameter(n=4)
-      dimension a(n)
-      do i=1,n
-      a(i)=i
-      enddo
-   10 print *,(a(i),i=1,n)
-      if(nextp(n,a)) go to 10
-      end
-
-      function nextp(n,a)
-      integer n,a,i,j,k,t
-      logical nextp
-      dimension a(n)
-      i=n-1
-   10 if(a(i).lt.a(i+1)) go to 20
-      i=i-1
-      if(i.eq.0) go to 20
-      go to 10
-   20 j=i+1
-      k=n
-   30 t=a(j)
-      a(j)=a(k)
-      a(k)=t
-      j=j+1
-      k=k-1
-      if(j.lt.k) go to 30
-      j=i
-      if(j.ne.0) go to 40
-      nextp=.false.
-      return
-   40 j=j+1
-      if(a(j).lt.a(i)) go to 40
-      t=a(i)
-      a(i)=a(j)
-      a(j)=t
-      nextp=.true.
-      end
+program allperm
+    implicit none
+    integer :: n, i
+    integer, allocatable :: a(:)
+    read *, n
+    allocate(a(n))
+    a = [ (i, i = 1, n) ]
+    call perm(1)
+    deallocate(a)
+contains
+    recursive subroutine perm(i)
+        integer :: i, j, t
+        if (i == n) then
+            print *, a
+        else
+            do j = i, n
+                t = a(i)
+                a(i) = a(j)
+                a(j) = t
+                call perm(i + 1)
+                t = a(i)
+                a(i) = a(j)
+                a(j) = t
+            end do
+        end if
+    end subroutine
+end program

Task/Permutations/Fortran/permutations-3.f

@@ -0,0 +1,41 @@
+      program nptest
+      integer n,i,a
+      logical nextp
+      external nextp
+      parameter(n=4)
+      dimension a(n)
+      do i=1,n
+      a(i)=i
+      enddo
+   10 print *,(a(i),i=1,n)
+      if(nextp(n,a)) go to 10
+      end
+
+      function nextp(n,a)
+      integer n,a,i,j,k,t
+      logical nextp
+      dimension a(n)
+      i=n-1
+   10 if(a(i).lt.a(i+1)) go to 20
+      i=i-1
+      if(i.eq.0) go to 20
+      go to 10
+   20 j=i+1
+      k=n
+   30 t=a(j)
+      a(j)=a(k)
+      a(k)=t
+      j=j+1
+      k=k-1
+      if(j.lt.k) go to 30
+      j=i
+      if(j.ne.0) go to 40
+      nextp=.false.
+      return
+   40 j=j+1
+      if(a(j).lt.a(i)) go to 40
+      t=a(i)
+      a(i)=a(j)
+      a(j)=t
+      nextp=.true.
+      end