program main implicit none integer::n(1:4),m(1:4) integer,allocatable::x(:),y(:) integer::hit,blow,phit,pblow,i,j data n/0,1,2,3/ allocate(x(4),y(4)) call get(n,hit,blow) if(hit.eq.4) return ! selection if(hit+blow.ne.4) then do i=1,4 phit = hit pblow = blow m = n do j=0,9 if(ANY(n.eq.j)) cycle m(i) = j call get(m,hit,blow) if(hit.eq.4) then return else if(hit+blow.eq.4) then n = m goto 10 else if(hit+blow.gt.phit+pblow) then n = m exit end if end do end do end if 10 continue ! shuffle x = n y = qsort(x) n = y if(hit.eq.4) then return end if do call get(n,hit,blow) if(hit.eq.4) then return end if call next_permutation(n) end do contains subroutine get(n,hit,blow) integer::n(1:4) integer::hit,blow print '(i0," ",i0," ",i0," ",i0)',n read *,hit,blow end subroutine get subroutine next_permutation(array) implicit none integer::array(:),d,i,j,k,swap d = 4 do i=d,2,-1 if(array(i-1).lt.array(i)) exit end do do j=d,i+1,-1 if(array(i-1).lt.array(j)) exit end do swap = array(i-1) array(i-1) = array(j) array(j) = swap do k=0, (d-1-i)/2 swap = array(i+k) array(i+k) = array(d-k) array(d-k) = swap end do end subroutine next_permutation recursive function qsort(x) result(y) integer,intent(in) ::x(:) integer,allocatable::y(:) integer::pivot,total total = size(x) if (total <=1) then y = x else pivot = x(total/2) y = [qsort(pack(x, x .lt. pivot)), & pack(x, x .eq. pivot), & qsort(pack(x, x .gt. pivot))] endif end function qsort end program main