Project Euler - Problem 1 - Tcl

# If we list all the natural numbers below 10 that are multiples of 3 or 5, we get 3, 5, 6 and 9. The sum of these multiples is 23.
# Find the sum of all the multiples of 3 or 5 below 1000.
proc Problem1 {} {

 set items {}

 for {set idx 3} {$idx<1000} {incr idx 3} {
  lappend items $idx
 }

 for {set idx 5} {$idx<1000} {incr idx 5} {
  if { [lsearch $items $idx] < 0 } {
   lappend items $idx
  }
 }

 set rval 0
 foreach item $items {
  set rval [expr $rval + $item]
 }
  

 return $rval
}
# solution: 233168