WeixiangYan/CodeTransOcean huggingface dataset:
Task: Tree traversal



C#: using System;
using System.Collections.Generic;
using System.Linq;

class Node
{
    int Value;
    Node Left;
    Node Right;

    Node(int value = default(int), Node left = default(Node), Node right = default(Node))
    {
        Value = value;
        Left = left;
        Right = right;
    }

    IEnumerable<int> Preorder()
    {
        yield return Value;
        if (Left != null)
            foreach (var value in Left.Preorder())
                yield return value;
        if (Right != null)
            foreach (var value in Right.Preorder())
                yield return value;
    }

    IEnumerable<int> Inorder()
    {
        if (Left != null)
            foreach (var value in Left.Inorder())
                yield return value;
        yield return Value;
        if (Right != null)
            foreach (var value in Right.Inorder())
                yield return value;
    }

    IEnumerable<int> Postorder()
    {
        if (Left != null)
            foreach (var value in Left.Postorder())
                yield return value;
        if (Right != null)
            foreach (var value in Right.Postorder())
                yield return value;
        yield return Value;
    }

    IEnumerable<int> LevelOrder()
    {
        var queue = new Queue<Node>();
        queue.Enqueue(this);
        while (queue.Any())
        {
            var node = queue.Dequeue();
            yield return node.Value;
            if (node.Left != null)
                queue.Enqueue(node.Left);
            if (node.Right != null)
                queue.Enqueue(node.Right);
        }
    }

    static void Main()
    {
        var tree = new Node(1, new Node(2, new Node(4, new Node(7)), new Node(5)), new Node(3, new Node(6, new Node(8), new Node(9))));
        foreach (var traversal in new Func<IEnumerable<int>>[] { tree.Preorder, tree.Inorder, tree.Postorder, tree.LevelOrder })
            Console.WriteLine("{0}:\t{1}", traversal.Method.Name, string.Join(" ", traversal()));
    }
}








Fortran:       IF (STYLE.EQ."PRE")  CALL OUT(HAS)
      IF (LINKL(HAS).GT.0) CALL TARZAN(LINKL(HAS),STYLE)
      IF (STYLE.EQ."IN")   CALL OUT(HAS)
      IF (LINKR(HAS).GT.0) CALL TARZAN(LINKR(HAS),STYLE)
      IF (STYLE.EQ."POST") CALL OUT(HAS)
Task: Tree traversal


C++: #include <boost/scoped_ptr.hpp>
#include <iostream>
#include <queue>

template<typename T>
class TreeNode {
public:
  TreeNode(const T& n, TreeNode* left = NULL, TreeNode* right = NULL)
    : mValue(n),
      mLeft(left),
      mRight(right) {}

  T getValue() const {
    return mValue;
  }

  TreeNode* left() const {
    return mLeft.get();
  }

  TreeNode* right() const {
    return mRight.get();
  }

  void preorderTraverse() const {
    std::cout << " " << getValue();
    if(mLeft)  { mLeft->preorderTraverse();  }
    if(mRight) { mRight->preorderTraverse(); }
  }

  void inorderTraverse() const {
    if(mLeft)  { mLeft->inorderTraverse();  }
    std::cout << " " << getValue();
    if(mRight) { mRight->inorderTraverse(); }
  }

  void postorderTraverse() const {
    if(mLeft)  { mLeft->postorderTraverse();  }
    if(mRight) { mRight->postorderTraverse(); }
    std::cout << " " << getValue();
  }

  void levelorderTraverse() const {
    std::queue<const TreeNode*> q;
    q.push(this);

    while(!q.empty()) {
      const TreeNode* n = q.front();
      q.pop();
      std::cout << " " << n->getValue();

      if(n->left())  { q.push(n->left());  }
      if(n->right()) { q.push(n->right()); }
    }
  }

protected:
  T mValue;
  boost::scoped_ptr<TreeNode> mLeft;
  boost::scoped_ptr<TreeNode> mRight;

private:
  TreeNode();
};

int main() {
  TreeNode<int> root(1,
    new TreeNode<int>(2,
      new TreeNode<int>(4,
        new TreeNode<int>(7)),
      new TreeNode<int>(5)),
    new TreeNode<int>(3,
      new TreeNode<int>(6,
        new TreeNode<int>(8),
        new TreeNode<int>(9))));

  std::cout << "preorder:   ";
  root.preorderTraverse();
  std::cout << std::endl;

  std::cout << "inorder:    ";
  root.inorderTraverse();
  std::cout << std::endl;

  std::cout << "postorder:  ";
  root.postorderTraverse();
  std::cout << std::endl;

  std::cout << "level-order:";
  root.levelorderTraverse();
  std::cout << std::endl;

  return 0;
}









Fortran:       IF (STYLE.EQ."PRE")  CALL OUT(HAS)
      IF (LINKL(HAS).GT.0) CALL TARZAN(LINKL(HAS),STYLE)
      IF (STYLE.EQ."IN")   CALL OUT(HAS)
      IF (LINKR(HAS).GT.0) CALL TARZAN(LINKR(HAS),STYLE)
      IF (STYLE.EQ."POST") CALL OUT(HAS)
Task: Tree traversal

C: #include <stdlib.h>
#include <stdio.h>

typedef struct node_s
{
  int value;
  struct node_s* left;
  struct node_s* right;
} *node;

node tree(int v, node l, node r)
{
  node n = malloc(sizeof(struct node_s));
  n->value = v;
  n->left  = l;
  n->right = r;
  return n;
}

void destroy_tree(node n)
{
  if (n->left)
    destroy_tree(n->left);
  if (n->right)
    destroy_tree(n->right);
  free(n);
}

void preorder(node n, void (*f)(int))
{
  f(n->value);
  if (n->left)
    preorder(n->left, f);
  if (n->right)
    preorder(n->right, f);
}

void inorder(node n, void (*f)(int))
{
  if (n->left)
    inorder(n->left, f);
  f(n->value);
  if (n->right)
    inorder(n->right, f);
}

void postorder(node n, void (*f)(int))
{
  if (n->left)
    postorder(n->left, f);
  if (n->right)
    postorder(n->right, f);
  f(n->value);
}


typedef struct qnode_s
{
  struct qnode_s* next;
  node value;
} *qnode;

typedef struct { qnode begin, end; } queue;

void enqueue(queue* q, node n)
{
  qnode node = malloc(sizeof(struct qnode_s));
  node->value = n;
  node->next = 0;
  if (q->end)
    q->end->next = node;
  else
    q->begin = node;
  q->end = node;
}

node dequeue(queue* q)
{
  node tmp = q->begin->value;
  qnode second = q->begin->next;
  free(q->begin);
  q->begin = second;
  if (!q->begin)
    q->end = 0;
  return tmp;
}

int queue_empty(queue* q)
{
  return !q->begin;
}

void levelorder(node n, void(*f)(int))
{
  queue nodequeue = {};
  enqueue(&nodequeue, n);
  while (!queue_empty(&nodequeue))
  {
    node next = dequeue(&nodequeue);
    f(next->value);
    if (next->left)
      enqueue(&nodequeue, next->left);
    if (next->right)
      enqueue(&nodequeue, next->right);
  }
}

void print(int n)
{
  printf("%d ", n);
}

int main()
{
  node n = tree(1,
                tree(2,
                     tree(4,
                          tree(7, 0, 0),
                          0),
                     tree(5, 0, 0)),
                tree(3,
                     tree(6,
                          tree(8, 0, 0),
                          tree(9, 0, 0)),
                     0));

  printf("preorder:    ");
  preorder(n, print);
  printf("\n");

  printf("inorder:     ");
  inorder(n, print);
  printf("\n");

  printf("postorder:   ");
  postorder(n, print);
  printf("\n");

  printf("level-order: ");
  levelorder(n, print);
  printf("\n");

  destroy_tree(n);

  return 0;
}










Fortran:       IF (STYLE.EQ."PRE")  CALL OUT(HAS)
      IF (LINKL(HAS).GT.0) CALL TARZAN(LINKL(HAS),STYLE)
      IF (STYLE.EQ."IN")   CALL OUT(HAS)
      IF (LINKR(HAS).GT.0) CALL TARZAN(LINKR(HAS),STYLE)
      IF (STYLE.EQ."POST") CALL OUT(HAS)
Task: Tree traversal





Java: import java.util.*;

public class TreeTraversal {

        static class Node<T> {
		T value;
		Node<T> left;
		Node<T> right;

		Node(T value) {
			this.value = value;
		}

		void visit() {
			System.out.print(this.value + " ");
		}
	}

	static enum ORDER {
		PREORDER, INORDER, POSTORDER, LEVEL
	}
        
        static <T> void traverse(Node<T> node, ORDER order) {
		if (node == null) {
			return;
		}
		switch (order) {
		case PREORDER:
			node.visit();
			traverse(node.left, order);
			traverse(node.right, order);
			break;
		case INORDER:
			traverse(node.left, order);
			node.visit();
			traverse(node.right, order);
			break;
		case POSTORDER:
			traverse(node.left, order);
			traverse(node.right, order);
			node.visit();
			break;
		case LEVEL:
			Queue<Node<T>> queue = new LinkedList<>();
			queue.add(node);
			while(!queue.isEmpty()){
				Node<T> next = queue.remove();
				next.visit();
				if(next.left!=null)
					queue.add(next.left);
				if(next.right!=null)
					queue.add(next.right);
			}
		}
	}	

	public static void main(String[] args) {

		Node<Integer> one = new Node<Integer>(1);
		Node<Integer> two = new Node<Integer>(2);
		Node<Integer> three = new Node<Integer>(3);
		Node<Integer> four = new Node<Integer>(4);
		Node<Integer> five = new Node<Integer>(5);
		Node<Integer> six = new Node<Integer>(6);
		Node<Integer> seven = new Node<Integer>(7);
		Node<Integer> eight = new Node<Integer>(8);
		Node<Integer> nine = new Node<Integer>(9);
		
		one.left = two;
		one.right = three;
		two.left = four;
		two.right = five;
		three.left = six;
		four.left = seven;
		six.left = eight;
		six.right = nine;

		traverse(one, ORDER.PREORDER);
		System.out.println(); 
		traverse(one, ORDER.INORDER);
		System.out.println();
		traverse(one, ORDER.POSTORDER);
		System.out.println();
		traverse(one, ORDER.LEVEL);
		
	}
}






Fortran:       IF (STYLE.EQ."PRE")  CALL OUT(HAS)
      IF (LINKL(HAS).GT.0) CALL TARZAN(LINKL(HAS),STYLE)
      IF (STYLE.EQ."IN")   CALL OUT(HAS)
      IF (LINKR(HAS).GT.0) CALL TARZAN(LINKR(HAS),STYLE)
      IF (STYLE.EQ."POST") CALL OUT(HAS)
Task: Tree traversal







Python: from collections import namedtuple
 
Node = namedtuple('Node', 'data, left, right')
tree = Node(1,
            Node(2,
                 Node(4,
                      Node(7, None, None),
                      None),
                 Node(5, None, None)),
            Node(3,
                 Node(6,
                      Node(8, None, None),
                      Node(9, None, None)),
                 None))
 
def printwithspace(i):
    print(i, end=' ')

def dfs(order, node, visitor):
    if node is not None:
        for action in order:
            if action == 'N':
                visitor(node.data)
            elif action == 'L':
                dfs(order, node.left, visitor)
            elif action == 'R':
                dfs(order, node.right, visitor)
                
def preorder(node, visitor = printwithspace):
    dfs('NLR', node, visitor)
 
def inorder(node, visitor = printwithspace):
    dfs('LNR', node, visitor)
 
def postorder(node, visitor = printwithspace):
    dfs('LRN', node, visitor)
 
def ls(node, more, visitor, order='TB'):
    "Level-based Top-to-Bottom or Bottom-to-Top tree search"
    if node:
        if more is None:
            more = []
        more += [node.left, node.right]
    for action in order:
        if action == 'B' and more:
            ls(more[0], more[1:], visitor, order)
        elif action == 'T' and node:
            visitor(node.data)

def levelorder(node, more=None, visitor = printwithspace):
    ls(node, more, visitor, 'TB') 
 

def reverse_preorder(node, visitor = printwithspace):
    dfs('RLN', node, visitor)
    
def bottom_up_order(node, more=None, visitor = printwithspace, order='BT'):
    ls(node, more, visitor, 'BT')


if __name__ == '__main__':
    w = 10
    for traversal in [preorder, inorder, postorder, levelorder, 
                      reverse_preorder, bottom_up_order]:
        if traversal == reverse_preorder:
            w = 20
            print('\nThe generalisation of function dfs allows:')
        if traversal == bottom_up_order:
            print('The generalisation of function ls allows:')
        print(f"{traversal.__name__:>{w}}:", end=' ')
        traversal(tree)
        print()




Fortran:       IF (STYLE.EQ."PRE")  CALL OUT(HAS)
      IF (LINKL(HAS).GT.0) CALL TARZAN(LINKL(HAS),STYLE)
      IF (STYLE.EQ."IN")   CALL OUT(HAS)
      IF (LINKR(HAS).GT.0) CALL TARZAN(LINKR(HAS),STYLE)
      IF (STYLE.EQ."POST") CALL OUT(HAS)
Task: Tree traversal








VB: Public Value As Integer
Public LeftChild As TreeItem
Public RightChild As TreeItem



Fortran:       IF (STYLE.EQ."PRE")  CALL OUT(HAS)
      IF (LINKL(HAS).GT.0) CALL TARZAN(LINKL(HAS),STYLE)
      IF (STYLE.EQ."IN")   CALL OUT(HAS)
      IF (LINKR(HAS).GT.0) CALL TARZAN(LINKR(HAS),STYLE)
      IF (STYLE.EQ."POST") CALL OUT(HAS)
Task: Tree traversal






PHP: class Node {
    private $left;
    private $right;
    private $value;

    function __construct($value) {
        $this->value = $value;
    }

    public function getLeft() {
        return $this->left;
    }
    public function getRight() {
        return $this->right;
    }
    public function getValue() {
        return $this->value;
    }

    public function setLeft($value) {
        $this->left = $value;
    }
    public function setRight($value) {
        $this->right = $value;
    }
    public function setValue($value) {
        $this->value = $value;
    }
}

class TreeTraversal {

    public function preOrder(Node $n) {
        echo $n->getValue() . " ";
        if($n->getLeft() != null) {
            $this->preOrder($n->getLeft());
        }
        if($n->getRight() != null){
            $this->preOrder($n->getRight());
        }
    }

    public function inOrder(Node $n) {
        if($n->getLeft() != null) {
            $this->inOrder($n->getLeft());
        }
        echo $n->getValue() . " ";
        if($n->getRight() != null){
            $this->inOrder($n->getRight());
        }

    }

    public function postOrder(Node $n) {
        if($n->getLeft() != null) {
            $this->postOrder($n->getLeft());
        }
        if($n->getRight() != null){
            $this->postOrder($n->getRight());
        }
        echo $n->getValue() . " ";
    }

    public function levelOrder($arg) {
        $q[] = $arg;
        while (!empty($q)) {
            $n = array_shift($q);
            echo $n->getValue() . " ";
            if($n->getLeft() != null) {
                $q[] = $n->getLeft();
            }
            if($n->getRight() != null){
                $q[] = $n->getRight();
            }
        }
    }
}

$arr = [];
for ($i=1; $i < 10; $i++) {
    $arr[$i] = new Node($i);
}

$arr[6]->setLeft($arr[8]);
$arr[6]->setRight($arr[9]);
$arr[3]->setLeft($arr[6]);
$arr[4]->setLeft($arr[7]);
$arr[2]->setLeft($arr[4]);
$arr[2]->setRight($arr[5]);
$arr[1]->setLeft($arr[2]);
$arr[1]->setRight($arr[3]);

$tree = new TreeTraversal($arr);

echo "preorder:\t";
$tree->preOrder($arr[1]);
echo "\ninorder:\t";
$tree->inOrder($arr[1]);
echo "\npostorder:\t";
$tree->postOrder($arr[1]);
echo "\nlevel-order:\t";
$tree->levelOrder($arr[1]);





Fortran:       IF (STYLE.EQ."PRE")  CALL OUT(HAS)
      IF (LINKL(HAS).GT.0) CALL TARZAN(LINKL(HAS),STYLE)
      IF (STYLE.EQ."IN")   CALL OUT(HAS)
      IF (LINKR(HAS).GT.0) CALL TARZAN(LINKR(HAS),STYLE)
      IF (STYLE.EQ."POST") CALL OUT(HAS)
Task: Tree traversal






PHP: class Node {
    private $left;
    private $right;
    private $value;

    function __construct($value) {
        $this->value = $value;
    }

    public function getLeft() {
        return $this->left;
    }
    public function getRight() {
        return $this->right;
    }
    public function getValue() {
        return $this->value;
    }

    public function setLeft($value) {
        $this->left = $value;
    }
    public function setRight($value) {
        $this->right = $value;
    }
    public function setValue($value) {
        $this->value = $value;
    }
}

class TreeTraversal {

    public function preOrder(Node $n) {
        echo $n->getValue() . " ";
        if($n->getLeft() != null) {
            $this->preOrder($n->getLeft());
        }
        if($n->getRight() != null){
            $this->preOrder($n->getRight());
        }
    }

    public function inOrder(Node $n) {
        if($n->getLeft() != null) {
            $this->inOrder($n->getLeft());
        }
        echo $n->getValue() . " ";
        if($n->getRight() != null){
            $this->inOrder($n->getRight());
        }

    }

    public function postOrder(Node $n) {
        if($n->getLeft() != null) {
            $this->postOrder($n->getLeft());
        }
        if($n->getRight() != null){
            $this->postOrder($n->getRight());
        }
        echo $n->getValue() . " ";
    }

    public function levelOrder($arg) {
        $q[] = $arg;
        while (!empty($q)) {
            $n = array_shift($q);
            echo $n->getValue() . " ";
            if($n->getLeft() != null) {
                $q[] = $n->getLeft();
            }
            if($n->getRight() != null){
                $q[] = $n->getRight();
            }
        }
    }
}

$arr = [];
for ($i=1; $i < 10; $i++) {
    $arr[$i] = new Node($i);
}

$arr[6]->setLeft($arr[8]);
$arr[6]->setRight($arr[9]);
$arr[3]->setLeft($arr[6]);
$arr[4]->setLeft($arr[7]);
$arr[2]->setLeft($arr[4]);
$arr[2]->setRight($arr[5]);
$arr[1]->setLeft($arr[2]);
$arr[1]->setRight($arr[3]);

$tree = new TreeTraversal($arr);

echo "preorder:\t";
$tree->preOrder($arr[1]);
echo "\ninorder:\t";
$tree->inOrder($arr[1]);
echo "\npostorder:\t";
$tree->postOrder($arr[1]);
echo "\nlevel-order:\t";
$tree->levelOrder($arr[1]);
Task: List comprehensions



C#: using System.Linq;

static class Program
{
  static void Main()
  {
    var ts =
      from a in Enumerable.Range(1, 20)
      from b in Enumerable.Range(a, 21 - a)
      from c in Enumerable.Range(b, 21 - b)
      where a * a + b * b == c * c
      select new { a, b, c };

      foreach (var t in ts)
        System.Console.WriteLine("{0}, {1}, {2}", t.a, t.b, t.c);
  }
}









Ada: with Ada.Text_IO; use Ada.Text_IO;
with Ada.Containers.Doubly_Linked_Lists;

procedure Pythagore_Set is

   type Triangles is array (1 .. 3) of Positive;

   package Triangle_Lists is new Ada.Containers.Doubly_Linked_Lists (
      Triangles);
   use Triangle_Lists;

   function Find_List (Upper_Bound : Positive) return List is
      L : List := Empty_List;
   begin
      for A in 1 .. Upper_Bound loop
         for B in A + 1 .. Upper_Bound loop
            for C in B + 1 .. Upper_Bound loop
               if ((A * A + B * B) = C * C) then
                  Append (L, (A, B, C));
               end if;
            end loop;
         end loop;
      end loop;
      return L;
   end Find_List;

   Triangle_List : List;
   C             : Cursor;
   T             : Triangles;

begin
   Triangle_List := Find_List (Upper_Bound => 20);

   C := First (Triangle_List);
   while Has_Element (C) loop
      T := Element (C);
      Put
        ("(" &
         Integer'Image (T (1)) &
         Integer'Image (T (2)) &
         Integer'Image (T (3)) &
         ") ");
      Next (C);
   end loop;
end Pythagore_Set;
Task: List comprehensions

C: for (int i = f + 1; i <= t; i ++) { e = e->nx = listNew(sizeof i, &i); }











Ada: with Ada.Text_IO; use Ada.Text_IO;
with Ada.Containers.Doubly_Linked_Lists;

procedure Pythagore_Set is

   type Triangles is array (1 .. 3) of Positive;

   package Triangle_Lists is new Ada.Containers.Doubly_Linked_Lists (
      Triangles);
   use Triangle_Lists;

   function Find_List (Upper_Bound : Positive) return List is
      L : List := Empty_List;
   begin
      for A in 1 .. Upper_Bound loop
         for B in A + 1 .. Upper_Bound loop
            for C in B + 1 .. Upper_Bound loop
               if ((A * A + B * B) = C * C) then
                  Append (L, (A, B, C));
               end if;
            end loop;
         end loop;
      end loop;
      return L;
   end Find_List;

   Triangle_List : List;
   C             : Cursor;
   T             : Triangles;

begin
   Triangle_List := Find_List (Upper_Bound => 20);

   C := First (Triangle_List);
   while Has_Element (C) loop
      T := Element (C);
      Put
        ("(" &
         Integer'Image (T (1)) &
         Integer'Image (T (2)) &
         Integer'Image (T (3)) &
         ") ");
      Next (C);
   end loop;
end Pythagore_Set;
Task: List comprehensions


C++: #include <vector>
#include <cmath>
#include <iostream>
#include <algorithm>
#include <iterator>

void list_comprehension( std::vector<int> & , int ) ;

int main( ) {
   std::vector<int> triangles ;
   list_comprehension( triangles , 20 ) ;
   std::copy( triangles.begin( ) , triangles.end( ) ,
	 std::ostream_iterator<int>( std::cout , " " ) ) ;
   std::cout << std::endl ;
   return 0 ;
}

void list_comprehension( std::vector<int> & numbers , int upper_border ) {
   for ( int a = 1 ; a < upper_border ; a++ ) {
      for ( int b = a + 1 ; b < upper_border ; b++ ) {
	 double c = pow( a * a + b * b , 0.5 ) ; 
	 if ( ( c * c ) < pow( upper_border , 2 ) + 1 ) {
	    if ( c == floor( c ) ) {
	       numbers.push_back( a ) ;
	       numbers.push_back( b ) ;	      
	       numbers.push_back( static_cast<int>( c ) ) ;
	    }
	 }
      }
   }
}










Ada: with Ada.Text_IO; use Ada.Text_IO;
with Ada.Containers.Doubly_Linked_Lists;

procedure Pythagore_Set is

   type Triangles is array (1 .. 3) of Positive;

   package Triangle_Lists is new Ada.Containers.Doubly_Linked_Lists (
      Triangles);
   use Triangle_Lists;

   function Find_List (Upper_Bound : Positive) return List is
      L : List := Empty_List;
   begin
      for A in 1 .. Upper_Bound loop
         for B in A + 1 .. Upper_Bound loop
            for C in B + 1 .. Upper_Bound loop
               if ((A * A + B * B) = C * C) then
                  Append (L, (A, B, C));
               end if;
            end loop;
         end loop;
      end loop;
      return L;
   end Find_List;

   Triangle_List : List;
   C             : Cursor;
   T             : Triangles;

begin
   Triangle_List := Find_List (Upper_Bound => 20);

   C := First (Triangle_List);
   while Has_Element (C) loop
      T := Element (C);
      Put
        ("(" &
         Integer'Image (T (1)) &
         Integer'Image (T (2)) &
         Integer'Image (T (3)) &
         ") ");
      Next (C);
   end loop;
end Pythagore_Set;
Task: List comprehensions




Go: package main

import "fmt"

type (
    seq  []int
    sofs []seq
)

func newSeq(start, end int) seq {
    if end < start {
        end = start
    }
    s := make(seq, end-start+1)
    for i := 0; i < len(s); i++ {
        s[i] = start + i
    }
    return s
}

func newSofs() sofs {
    return sofs{seq{}}
}

func (s sofs) listComp(in seq, expr func(sofs, seq) sofs, pred func(seq) bool) sofs {
    var s2 sofs
    for _, t := range expr(s, in) {
        if pred(t) {
            s2 = append(s2, t)
        }
    }
    return s2
}

func (s sofs) build(t seq) sofs {
    var u sofs
    for _, ss := range s {
        for _, tt := range t {
            uu := make(seq, len(ss))
            copy(uu, ss)
            uu = append(uu, tt)
            u = append(u, uu)
        }
    }
    return u
}

func main() {
    pt := newSofs()
    in := newSeq(1, 20)
    expr := func(s sofs, t seq) sofs {
        return s.build(t).build(t).build(t)
    }
    pred := func(t seq) bool {
        if len(t) != 3 {
            return false
        }
        return t[0]*t[0]+t[1]*t[1] == t[2]*t[2] && t[0] < t[1] && t[1] < t[2]
    }
    pt = pt.listComp(in, expr, pred)
    fmt.Println(pt)
}








Ada: with Ada.Text_IO; use Ada.Text_IO;
with Ada.Containers.Doubly_Linked_Lists;

procedure Pythagore_Set is

   type Triangles is array (1 .. 3) of Positive;

   package Triangle_Lists is new Ada.Containers.Doubly_Linked_Lists (
      Triangles);
   use Triangle_Lists;

   function Find_List (Upper_Bound : Positive) return List is
      L : List := Empty_List;
   begin
      for A in 1 .. Upper_Bound loop
         for B in A + 1 .. Upper_Bound loop
            for C in B + 1 .. Upper_Bound loop
               if ((A * A + B * B) = C * C) then
                  Append (L, (A, B, C));
               end if;
            end loop;
         end loop;
      end loop;
      return L;
   end Find_List;

   Triangle_List : List;
   C             : Cursor;
   T             : Triangles;

begin
   Triangle_List := Find_List (Upper_Bound => 20);

   C := First (Triangle_List);
   while Has_Element (C) loop
      T := Element (C);
      Put
        ("(" &
         Integer'Image (T (1)) &
         Integer'Image (T (2)) &
         Integer'Image (T (3)) &
         ") ");
      Next (C);
   end loop;
end Pythagore_Set;