Temperatures puzzle discussion

jmakellky · June 18, 2019, 8:12pm

My solution passes all the tests but when I submit, the score computer seems to freeze.

TwoSteps · June 19, 2019, 7:57am

We had an issue yesterday with the submits. It’s solved.

ankhati22 · July 8, 2019, 1:04pm

What are the testcases 7 and 8? they are not shown in the list of cases to execute. it ends at 6.

TwoSteps · July 8, 2019, 1:15pm

they are shown in the results panel, aren’t they?

ankhati22 · July 8, 2019, 2:02pm

results panel yes, and there I was surprised to learn I failed test 7. The test cases panel only goes to 6.

TwoSteps · July 8, 2019, 4:08pm

yes, there are two additional validators compared to the tests. Their names should be self-explanatory in any case you fail them.

TBali · July 21, 2019, 11:20am

I struggle with getting a BASH version work (I am completely incompetent in bash).
In the main loop I try to get abs value by this:
t=${myArray[$((i))]}
ta=${t#-}
tc=${closest#-}
Then trying to check if a new best solution found by this:
if [ $ta -lt $tc ] || [ [ $ta -eq $tc ] && [ $t -ge 0 ] ]
then
closest=$t
fi;
However the if statement is invalid. How to put it right? Thanks.

TBali · July 22, 2019, 7:52pm

okay, just a little web search solved it for me: replacing and -gt with the (( )) syntax.
if (( ( $ta < $tc ) || ( ( $ta == $tc ) && ( $t >= 0 ) ) ))

JBM · July 22, 2019, 11:25pm

If you go for double-parenthesis syntax, you don’t need the dollar signs anymore.

Single-bracket syntax is IMHO to be avoided completely, but there’s little reason you shoudn’t have found any luck with double brackets. What was the actual problem with your statement?

TBali · July 23, 2019, 7:17am

It was syntax error…
if [ $ta -lt $tc ] || [ [ $ta -eq $tc ] && [ $t -ge 0 ] ]

JBM · July 23, 2019, 10:02am

Single-bracket conditionals are a builtin in bash, but they strive to maintain compatibility with old-style conditionals using external command test. As such:

they don’t nest (at least, not directly)
they need a lot of escaping

Making your example to pass would need one of these:

closest to your example: [ $ta -lt $tc ] || [ $ $ta -eq $tc $ -a $ $t -ge 0 $ ]
Notice how the inner tests use parentheses, and they have to be escaped to be interpreted by [ not bash. (they’re actually not needed, it’s just to stick to your template)
&& and || have equal precedence in bash, and have a behavior equivalent to left-associative short-circuit, so in this case you actually don’t need any parentheses:
[ $ta -lt $tc ] || [ $ta -eq $tc ] && [ $t -ge 0 ]
or in a single expression:
test $ $ta -lt $tc $ -o $ \( $ta -eq $tc $ -a $ $t -ge 0 $ \)
that simplifies to:
test $ta -lt $tc -o $ta -eq $tc -a $t -ge 0

It happens to be ok here because the parameters are defined and non-zero-length, but so many things can go wrong when passing arguments from bash to test that it’s best practice to just always quote variables: "$t".

All of this has been obsolete for years: if you have [[ (you do), use it instead of [.

TBali · July 23, 2019, 4:10pm

Thanks! By a single post you at least tripled my bash knowledge…
It seems bash is a competent tool in the skilled hands, but that is definitely not mine… My only remaining ambition with bash is to… reach Legend in the next contest with it… ehm…correction… to cash in an extra achievement plus a hefty 25 XPs in the ‘Horse racing’ duals easy training puzzle.

TBali · July 27, 2019, 6:55pm

I am not sure if the provided input parser skeleton for OCaml is correct:

(* Auto-generated code below aims at helping you parse )
( the standard input according to the problem statement. )
let n = int_of_string (input_line stdin) in ( the number of temperatures to analyse )
let line = input_line stdin in
for i = 0 to n - 1 do
( t: a temperature expressed as an integer ranging from -273 to 5526 )
let t = Scanf.sscanf line “%d” (fun t → (t)) in
();
done;
( Write an action using print_endline )
( To debug: prerr_endline “Debug message”; *)
print_endline “result”;

If I add only this line after the “let t” line, it always prints always prints the same first number from the input line:
prerr_endline(string_of_int t);

OCaml gurus: what do i miss?

Niako · July 28, 2019, 10:18am

The parser is indeed incorrect (sscanf always reads the first integer of the line).
Use something like that instead:

let n = int_of_string (input_line stdin) in
let temperatures = List.map int_of_string (String.split_on_char ' ' (input_line stdin)) in
List.iter (fun t -> prerr_endline (string_of_int t)) temperatures

Or alternatively (closer to the provided parser), replace sscanf by scanf (note the space in the format string to eat all whitespaces).

let n = int_of_string (input_line stdin) in
for i = 0 to n - 1 do
    let t = Scanf.scanf " %d" (fun t -> t) in
    prerr_endline (string_of_int t);
done;

TBali · July 28, 2019, 12:22pm

Thanks, that solved it.

Sylvain.Guelle · August 2, 2019, 7:50pm

Bonjour,
c’est pas très propre ce que j’ai écrit , mais en testant mon code dans jsfiddle.net , j’obtient les bons résultats mais ça ne fonctionne pas sur codingame

timmy1691 · August 8, 2019, 11:45pm

Is that the same as writing an except block for a different error? Im still learnig code so not sure.

TwoSteps · August 9, 2019, 1:50pm

It’s difficult to help you if you don’t tell us what’s not working for you.

What have you tested? What is blocking you?

AndyYoung · August 16, 2019, 9:46pm

I am troubleshooting the following code for the Puzzle “Temperatures” related to finding temperatures closest to zero. Programming in C, I have tested it dozens of times on three different IDEs (Code::Blocks, Dev-C++, and CLion), all of which work perfectly. However, when I run in the CodinGame IDE, it produces an error. Specifically, it sends the value 1 to stdout instead of the expected correct value closest to zero. The strategy I used was to place the scanf() temperatures into an array of size n, order them by the absolute value (abs()) of the number, and printf() the value in the first index of the ordered array. Some simple program control at the end deals with the case of selecting positive over negative values when their absolute values are equal (e.g., if selecting between -5 and 5, choose 5). Does CodinGame not accept arrays or pointers?

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <math.h>
// User defined function prototype
void swap(int *xp, int *yp);

int main()
{
    int n; // the number of temperatures to analyse
    int temp[n]; // Declare an array of size n
    scanf("%d", &n); // System reads size
    for (int i = 0; i < n; i++) 
    {
        int t;
        temp[i] = scanf("%d", &t); //<-- inputs scanf() into an array
    }

    int j, i, min_idx;

    for ( i = 0; i < n-1; i++ )
    {
        min_idx = i;
        for ( j = i+1; j < n; j++ )
        {
            if ( abs(temp[j]) < abs(temp[min_idx]) )
            {
                min_idx = j;
            }
        }
        // User defined function to swap array elements
        swap(&temp[min_idx], &temp[i]); 
    }
    // Program control to deal with 5 or -5
    if ( abs(temp[0]) == abs(temp[1]) && temp[1] > temp[0] )
    {
        printf("%d\n", temp[1]);
    }
    else
        printf("%d\n", temp[0]);
    
    return 0;
}

/*swap() -- user defined function that swaps values from an array. */
void swap(int *xp, int *yp)
{
    int temp = *xp;
    *xp = *yp;
    *yp = temp;
}

RoboStac · August 16, 2019, 9:55pm

temp[i] = scanf("%d", &t);

scanf returns the number of items scanned, so you just fill your array with 1’s.