Task: Subset sum problem




Go: package main

import "fmt"

type ww struct {
    word   string
    weight int
}

var input = []*ww{
    {"alliance", -624},
    {"archbishop", -915},
    {"balm", 397},
    {"bonnet", 452},
    {"brute", 870},
    {"centipede", -658},
    {"cobol", 362},
    {"covariate", 590},
    {"departure", 952},
    {"deploy", 44},
    {"diophantine", 645},
    {"efferent", 54},
    {"elysee", -326},
    {"eradicate", 376},
    {"escritoire", 856},
    {"exorcism", -983},
    {"fiat", 170},
    {"filmy", -874},
    {"flatworm", 503},
    {"gestapo", 915},
    {"infra", -847},
    {"isis", -982},
    {"lindholm", 999},
    {"markham", 475},
    {"mincemeat", -880},
    {"moresby", 756},
    {"mycenae", 183},
    {"plugging", -266},
    {"smokescreen", 423},
    {"speakeasy", -745},
    {"vein", 813},
}

type sss struct {
    subset []*ww
    sum    int
}

func main() {
    ps := []sss{{nil, 0}}
    for _, i := range input {
        pl := len(ps)
        for j := 0; j < pl; j++ {
            subset := append([]*ww{i}, ps[j].subset...)
            sum := i.weight + ps[j].sum
            if sum == 0 {
                fmt.Println("this subset sums to 0:")
                for _, i := range subset {
                    fmt.Println(*i)
                }
                return
            }
            ps = append(ps, sss{subset, sum})
        }
    }
    fmt.Println("no subset sums to 0")
}








Ada: with Ada.Text_IO; use Ada.Text_IO;
with Ada.Strings.Unbounded; use Ada.Strings.Unbounded;
procedure SubsetSum is
   function "+"(S:String) return Unbounded_String renames To_Unbounded_String;
   type Point is record
      str : Unbounded_String;
      num : Integer;
   end record;
   type Points is array (Natural range <>) of Point;
   type Indices is array (Natural range <>) of Natural;

   procedure Print (data : Points; list : Indices; len : Positive) is begin
      Put (len'Img & ":");
      for i in 0..len-1 loop
         Put (" "& To_String(data(list(i)).str));
      end loop; New_Line;
   end Print;

   function Check (data : Points; list : Indices; len : Positive) return Boolean is
      sum : Integer := 0;
   begin
      for i in 0..len-1 loop sum := sum + data(list(i)).num; end loop;
      return sum = 0;
   end Check;

   procedure Next (list : in out Indices; n, r : Positive ) is begin
      for i in reverse 0..r-1 loop
         if list(i)/=i+n-r then list(i):=list(i)+1;
            for j in i+1..r-1 loop list(j):=list(j-1)+1; end loop; exit;
         end if;
      end loop;
   end Next;

   data : constant Points := ((+"alliance", -624), (+"archbishop", -915),
      (+"balm", 397), (+"bonnet", 452), (+"brute", 870),
      (+"centipede", -658), (+"cobol", 362), (+"covariate", 590),
      (+"departure", 952), (+"deploy", 44), (+"diophantine", 645),
      (+"efferent", 54), (+"elysee", -326), (+"eradicate", 376),
      (+"escritoire", 856), (+"exorcism", -983), (+"fiat", 170),
      (+"filmy", -874), (+"flatworm", 503), (+"gestapo", 915),
      (+"infra", -847), (+"isis", -982), (+"lindholm", 999),
      (+"markham", 475), (+"mincemeat", -880), (+"moresby", 756),
      (+"mycenae", 183), (+"plugging", -266), (+"smokescreen", 423),
      (+"speakeasy", -745), (+"vein", 813));
   list, last : Indices (data'Range);
begin
   for len in 2..data'Length loop
      for i in 0..len-1 loop list(i):=i; end loop;
      loop
         if Check(data, list, len) then Print(data, list, len); exit; end if;
         last := list;
         Next(list, data'Length, len);
         exit when last=list;
      end loop;
   end loop;
end SubsetSum;