Long stairs: Difference between revisions

=={{header|jq}}==

{{works with|jq}}

'''Works with gojq, the Go implementation of jq'''

Neither the C nor the Go-based implmentations of jq currently have a

built-in PRNG, so for the present task

/dev/urandom is used as a source of entropy by invoking jq as follows:

<pre>

cat /dev/urandom | tr -cd '0-9' | fold -w 1 | jq -nrf long-stairs.jq

</pre>

where long-stairs.jq contains the jq program shown below.

For simplicity and since the intermediate output has the character of

a probe, the program uses `debug` statements to show the intermediate results.

<lang jq># 0 <= output < $n

def rand($n):

def ntimes(f): range(0; .) | f;

# input: an array of length ($n|tostring|length)

def r:

. as $in

| (join("") | tonumber) as $m

| if $m < $n then $m

else $in[1:] + [input] | r

end;

[$n | tostring | length | ntimes(input)] | r;

# $n specifies the number of iterations

def task($n):

(reduce range(1; $n + 1) as $trial (null;

.sbeh = 0

| .slen = 100

| .secs = 0

| until (.sbeh >= .slen;

.sbeh += 1

| reduce range(1;6) as $wiz (.;

if (rand( .slen) < .sbeh) then .sbeh += 1 else . end

| .slen += 1 )

| .secs += 1

| if ($trial == 1 and .secs > 599 and .secs < 610)

then ([.secs, .sbeh, .slen - .sbeh] | debug) as $debug | .

else .

end )

| .totalSecs += .secs

| .totalSteps += .slen ) ) ;

"Seconds steps behind steps ahead",

"------- ------------ -----------",

(1E4 as $n

| task($n)

| "\nAverage secs taken over \($n) trials: \(.totalSecs/$n)",

"Average final length of staircase: \(.totalSteps/$n)"

)</lang>

{{out}}

<pre>

Seconds steps behind steps ahead

------- ------------ -----------

["DEBUG:",[600,1916,1184]]

["DEBUG:",[601,1919,1186]]

["DEBUG:",[602,1920,1190]]

["DEBUG:",[603,1924,1191]]

["DEBUG:",[604,1926,1194]]

["DEBUG:",[605,1931,1194]]

["DEBUG:",[606,1934,1196]]

["DEBUG:",[607,1938,1197]]

["DEBUG:",[608,1942,1198]]

["DEBUG:",[609,1945,1200]]

Average secs taken over 10000 trials: 3211.962

Average final length of staircase: 16159.81

</pre>