Water collected between towers: Difference between revisions

 

<br>

 

=={{header|AppleScript}}==

{{Trans|JavaScript}}

 

 

-- waterCollected :: [Int] -> Int

 

 

on run

map(waterCollected, ¬

 

 

 

-- filter :: (a -> Bool) -> [a] -> [a]

return lst

end tell

{{Out}}

 

=={{header|AWK}}==

# syntax: GAWK -f WATER_COLLECTED_BETWEEN_TOWERS.AWK [-v debug={0|1}]

BEGIN {

function max(x,y) { return((x > y) ? x : y) }

function min(x,y) { return((x < y) ? x : y) }

{{out}}

<pre>

0 : 6,7,10,7,6

</pre>

 

=={{header|C}}==

Takes the integers as input from command line, prints out usage on incorrect invocation.

#include<stdlib.h>

#include<stdio.h>

return 0;

}

Output :

<pre>

Water collected : 0

</pre>

 

=={{header|C++}}==

#include <iostream>

#include <vector>

std::cin.get();

return 0;

 

{{out}}

0 water drops.

0 water drops.</pre>

 

=={{header|Clojure}}==

Similar two passes algorithm as many solutions here. First traverse left to right to find the highest tower on the left of each position, inclusive of the tower at the current position, than do the same to find the highest tower to the right of each position. Finally, compute the total water units held at any position as the difference of those two heights.

 

(defn trapped-water [towers]

(let [maxes #(reductions max %) ; the seq of increasing max values found in the input seq

mins (map min maxl maxr)] ; minimum highest surrounding tower per position

(reduce + (map - mins towers)))) ; sum up the trapped water per position

{{out}}

;; in the following, # is a tower block and ~ is trapped water:

;;

;; 5 3 7 2 6 4 5 9 1 2

(trapped-water [5 3 7 2 6 4 5 9 1 2]) ;; 14

 

=={{header|D}}==

{{Trans|C#}}

 

void main() {

writeln(" water units.");

}

 

{{out}}

Block 6 does not hold any water units.

Block 7 does not hold any water units.</pre>

 

=={{header|Erlang}}==

Implements a version that uses recursion to solve the problem functionally, using two passes without requiring list reversal or modifications. On the list iteration from head to tail, gather the largest element seen so far (being the highest one on the left). Once the list is scanned, each position returns the highest tower to its right as reported by its follower, along with the amount of water seen so far, which can then be used to calculate the value at the current position. Back at the first list element, the final result is gathered.

 

-module(watertowers).

-export([towers/1, demo/0]).

[io:format("~p -> ~p~n", [Case, towers(Case)]) || Case <- Cases],

ok.

 

{{out}}

=={{header|F_Sharp|F#}}==

see http://stackoverflow.com/questions/24414700/water-collected-between-towers/43779936#43779936 for an explanation of this code. It is proportional to the number of towers. Although the examples on stackoverflow claim this, the n they use is actually the distance between the two end towers and not the number of towers. Consider the case of a tower of height 5 at 1, a tower of height 10 at 39, and a tower of height 3 at 101.

(*

A solution I'd show to Euclid !!!!.

| _ -> l

fn (min n i) (max n i) g (e*(abs(n-i)-1))

{{out}}

<pre>

 

=={{header|Factor}}==

 

{ 1 5 3 7 2 }

{ 5 3 7 2 6 4 5 9 1 2 }

{ 8 7 7 6 }

{ 6 7 10 7 6 }

{{out}}

<pre>

 

=={{header|Go}}==

package main

 

fmt.Println(waterCollected([]int{8, 7, 7, 6}))

fmt.Println(waterCollected([]int{6, 7, 10, 7, 6}))

 

{{out}}

=={{header|Groovy}}==

 

Integer waterBetweenTowers(List<Integer> towers) {

// iterate over the vertical axis. There the amount of water each row can hold is

println "$it => total water: ${waterBetweenTowers it}"

}

 

{{out}}

Following the approach of slightly modified [http://stackoverflow.com/users/1416525/cdk cdk]'s Haskell solution at [http://stackoverflow.com/questions/24414700/amazon-water-collected-between-towers/ Stack Overflow]. As recommended in [http://h2.jaguarpaw.co.uk/posts/data-structures-matter/ Programming as if the Correct Data Structure (and Performance) Mattered] it uses [http://hackage.haskell.org/package/vector-0.12.0.1/docs/Data-Vector-Unboxed.html Vector] instead of Array:

 

import qualified Data.Vector.Unboxed as V

 

waterCollected :: Vector Int -> Int

waterCollected =

 

main :: IO ()

main =

mapM_

{{Out}}

<pre>2

0

0</pre>

=={{header|J}}==

Inspired by [[#Julia]].

 

'''Solution:'''

waterLevels=: collectLevels - ] NB. water levels for each tower

collectedWater=: +/@waterLevels NB. sum the units of water collected

 

'''Examples:'''

14

printTowers 5 3 7 2 6 4 5 9 1 2

TestResults =: 2 14 35 0 0 0 0

TestResults -: collectedWater &> TestTowers NB. check tests

 

=={{header|Java}}==

{{trans|D}}

public static void main(String[] args) {

int i = 1;

}

}

{{out}}

<pre>Block 1 holds 2 water units.

===ES5===

{{Trans|Haskell}}

'use strict';

 

 

//--> [2, 14, 35, 0, 0, 0, 0]

 

{{Out}}

 

===ES6===

{{Trans|Haskell}}

 

// waterCollected :: [Int] -> Int

 

 

 

 

// max :: Ord a => a -> a -> a

 

// min :: Ord a => a -> a -> a

 

// scanl :: (b -> a -> b) -> b -> [a] -> [b]

 

// scanl1 :: (a -> a -> a) -> [a] -> [a]

 

 

// scanr1 :: (a -> a -> a) -> [a] -> [a]

 

 

 

 

{{Out}}

 

=={{header|Julia}}==

Inspired to [[#Python]].

 

high_lft = vcat(0, accumulate(max, towers[1:end-1]))

high_rgt = vcat(reverse(accumulate(max, towers[end:-1:2])), 0)

towerprint(towers, watercollected(towers))

println()

 

{{out}}

=={{header|Kotlin}}==

{{trans|Python}}

 

fun waterCollected(tower: IntArray): Int {

println("${"%2d".format(waterCollected(tower))} from ${tower.contentToString()}")

}

 

{{out}}

0 from [8, 7, 7, 6]

0 from [6, 7, 10, 7, 6]

</pre>

 

=={{header|Perl}}==

use List::Util qw{ min max sum };

 

[ 8, 7, 7, 6 ],

[ 6, 7, 10, 7, 6 ],

{{Out}}

<pre>2 14 35 0 0 0 0</pre>

 

 

 

 

 

 

 

=={{header|PicoLisp}}==

(sum

'((A)

(5 6 7 8)

(8 7 7 6)

{{out}}

<pre>(2 14 35 0 0 0 0)</pre>

Based on the algorithm explained at [http://stackoverflow.com/questions/24414700/amazon-water-collected-between-towers/32135773#32135773 Stack Overflow]:

 

N = len(tower)

highest_left = [0] + [max(tower[:n]) for n in range(1,N)]

[6, 7, 10, 7, 6]]

 

{{Out}}

<pre>

 

[2, 14, 35, 0, 0, 0, 0]</pre>

 

=={{header|Racket}}==

(require racket/match)

 

[6 7 10 7 6]]))

(map water-collected-between-towers towerss))

 

When run produces no output -- meaning that the tests have run successfully.

 

=={{header|REXX}}==

===version 1===

Call bars '1 5 3 7 2'

Call bars '5 3 7 2 6 4 5 9 1 2'

Say ol

End

{{out}}

<pre>1 5 3 7 2 -> 2

 

===version 2, simple numeric list output===

exit /*stick a fork in it, we're all done. */

/*──────────────────────────────────────────────────────────────────────────────────────*/

tower: procedure; arg y; #=words(y); t.=0; L.=0 /*the T. array holds the tower heights.*/

end /*j*/

R.=0

end /*b*/

w.=0 /*rainwater collected.*/

do f=1 for #; if t.f>=L.f | t.f>=R.f then iterate /*rain between towers?*/

end /*f*/

<pre>

2 units of rainwater collected for: 1 5 3 7 2

 

===version 3, with ASCII art===

 

call tower 1 5 3 7 2

call tower 5 3 7 2 6 4 5 9 1 2

exit /*stick a fork in it, we're all done. */

/*──────────────────────────────────────────────────────────────────────────────────────*/

do j=1 for #; t.j=word(y,j); _=j-1 /*construct the towers; max height. */

L.j=max(t._, L._); t.0=max(t.0, t.j) /*left-most tallest tower; build scale.*/

end /*j*/

R.=0

end /*b*/

w.=0 /*rainwater collected.*/

do f=1 for #; if t.f>=L.f | t.f>=R.f then iterate /*rain between towers?*/

end /*f*/

p.= /*P. stores plot versions of towers. */

end /*h*/

end /*c*/

do z=t.0 by -1 to 0; say p.z /*display various tower floors & water.*/

end /*z*/

<pre>

7 ██

2 ██████████

1 ██████████ no units of rainwater collected

</pre>

 

=={{header|Ruby}}==

def a(array)

n=array.length

a([ 8, 7, 7, 6 ])

a([ 6, 7, 10, 7, 6 ])

'''output'''

<pre>

</pre>

 

 

(scheme write))

 

(5 6 7 8)

(8 7 7 6)

{{out}}

(5 3 7 2 6 4 5 9 1 2) -> 14

(2 6 3 5 2 8 1 4 2 2 5 3 5 7 4 1) -> 35

(1) -> 0

() -> 0

 

=={{header|Sidef}}==

gather { a.each {|e| take(m = max(m, e)) } }

}

[ 8, 7, 7, 6 ],

[ 6, 7, 10, 7, 6 ],

{{out}}

<pre>

[2, 14, 35, 0, 0, 0, 0]

</pre>

 

=={{header|Tcl}}==

Tcl makes for a surprisingly short and readable implementation, next to some of the more functional-oriented languages.

 

proc flood {ground} {

} {

puts [flood $p]:\t$p

 

{{out}}

0: 6 7 10 7 6</pre>

 

 

 

 

 

 

 

 

=={{header|zkl}}==

{{trans|Haskell}}

// compile max wall heights from left to right and right to left

// then each pair is left/right wall of that cell.

xs.reduce('wrap(s,x,a){ s=f(s,x); a.append(s); s },i,ss:=List());

ss

T(2, 6, 3, 5, 2, 8, 1, 4, 2, 2, 5, 3, 5, 7, 4, 1),

T(5, 5, 5, 5), T(5, 6, 7, 8),T(8, 7, 7, 6),

T(6, 7, 10, 7, 6) )

{{out}}

<pre>