How much time is remaining?

Question

The Program

You are given two strings, A and B. A is the current position at which your timer is at, and B is the position at which your timer will stop. Both strings are in the format m:ss. You must write a program that determines the amount of time left which should also be formatted as m:ss or mm:ss.

Example

0:00 0:01 -> 0:01
0:55 1:00 -> 0:05
1:45 3:15 -> 1:30

Answer 1

Excel, 6 Bytes

=B1-A1

Assuming A is in cell A1 and B is in cell B1

Answer 2

MATL, 17 7 bytes

YOd15XO

Input is a cell array of strings, in the form {'1:45' '3:15'} or {'1:45', '3:15'}.

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Explanation

YO     % Input cell array of strings (implicit). Convert to serial date numbers
d      % Difference
15XO   % Convert to format 15, i.e. 'HH:MM'. Display (implicit)

Answer 3

Bash + coreutils, 44 39 bytes

tr : \ |dc -e?r60*+r-r60*-60~rn58PA~rnn

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Explanation: using "1:45 3:15" as test case (last example). I show intermediary steps in quotes.

tr : \ |         # replace colons with spaces: "1 45 3 15"
dc -e?           # start dc script, push input to LIFO stack: "15 3 45 1"
     r60*+            # turn time B to total seconds: "195 45 1"
     r-r60*-          # turn time A to total seconds and get difference: "90"
     60~r             # turn difference (time left) to minutes and seconds: "1 30"
     n58P             # pop and print minutes, print colon (ASCII code 58): "30"
     A~rnn            # print seconds. Padding with zeroes is done by dividing by
                      #10 (A), and printing the quotient and the remainder.

Note that I don't check if the minute value needs zero padding, because the OP stated that the maximum value for m is 9.

---

Below is my original 44 bytes answer, that used the date command to turn the total time left in seconds to the m:ss format.

date -d@`tr : \ |dc -e?r60*+r-r60*-p` +%M:%S

Answer 4

Python 2, 90 87 83 80 bytes

Takes input like "2:45","5:01".

a,b=[60*int(s[-5:-3])+int(s[-2:])for s in input()]
print'%d:%02d'%divmod(b-a,60)

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Answer 5

C, 112 100 bytes

Thanks to @betseg for saving 11 bytes and thanks to @Johan du Toit for saving one byte!

i,j;f(char*a,char*b){i=atoi(b)-atoi(a);j=atoi(b+2)-atoi(a+2);j<0?i--,j+=60:0;printf("%d:%02d",i,j);}

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Answer 6

c, 86

f(a,b,c,d){scanf("%d:%d%d:%d",&a,&b,&c,&d);d+=(c-a)*60-b;printf("%d:%02d",d/60,d%60);}

Reads space-separated times from STDIN.

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Answer 7

Batch, 74 bytes

@set t=%2-(%1)
@set/as=%t::=*60+1%,m=s/60,t=s/10%%6
@echo %m%:%t%%s:~-1%

Replacing the : in the time with *60+1 converts it into an expression that calculates the number of seconds. Batch interprets leading zeros as octal so I prepend a 1 to the seconds to ensure decimal conversion; fortunately the two 1s cancel out.

Answer 8

MySQL, 13 22 bytes

select right(timediff(B,A),5)

expects the times in A and B.

Answer 9

C#, 72 bytes

using System;a=>b=>((DateTime.Parse(b)-DateTime.Parse(a))+"").Remove(5);

Takes input as strings. b="3:15" a="1:45".

Explanation:

Because DateTime.Parse() returns a Date in hh:mm:ss format, I am able to parse the result into a string using +"", then trim the trailing :00.

This works with hh:mm because there are both 60 seconds in a minute and 60 minutes in an hour.

0:01 0:00 returns 0:01

1:00 0:55 returns 0:05

3:15 1:45 returns 1:30

Answer 10

ECMAScript 6, 99 91 85 bytes

Single Line:

f=s=>s.split`:`.reduce((a,e,i)=>a+e*(!i?60:1),0);t=n=>~~(n/60)+":"+n%60;t(f(b)-f(a));

Slightly formatted:

f=s=>s.split`:`.reduce((a,e,i)=>a+e*(!i?60:1),0);
t=n=>~~(n/60)+":"+n%60;
t(f(b)-f(a));

I feel there could be some some savings in there.. but I am not seeing them at present.

Edit - excellent suggestions in the comments.

Answer 11

Bash + GNU utilities, 43

date -d@`date -f- +%s|dc -e??r-60/p` +%M:%S

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Explanation

         date -f- +%s                        # read in 2 line-delimited dates and output as number of seconds since the epoch
                     |dc -e                  # pipe to dc expression:
                           ??                # - read 2 input numbers
                             r-              # - reverse and subtract
                               60/           # - divide by 60
                                  p          # - output
        `                          `         # evaluate date|dc command
date -d@                             +%M:%S  # format seconds difference and output

Note the dc expression divides by 60, because date reads the input as H:MM instead of M:SS.

Answer 12

PHP, 55 53 bytes

<?=date('i:s',($s=strtotime)($argv[2])-$s($argv[1]));

takes input from command line arguments

Answer 13

Rebol, 5 bytes

b - a

Assuming I didn't miss any rules..

Rebol has arithmetic built-in for a number of literal data types. This also applies to its descendants such as Red

Answer 14

Haskell, 98 127 86 Bytes

r(m:_:s)=60*read[m]+read s
a#b|(d,m)<-divMod(r b-r a)60=show d++':':['0'|m<=9]++show m

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But I wonder if there are some library functions for this

EDIT: Removed import, also fixed an error where it showed m:s instead of m:ss

Also, well-formatted version:

convert :: String -> Integer
convert (a:_:b) = (read [a])*60+(read b)

diffTime :: String -> String -> String
diffTime s1 s2 = let (d,m) = divMod (c b-c a) 60 in show d ++ ":" ++ pad2d m

pad2d :: Int -> String
pad2d n = ['0'|n<=9]++show n

EDIT2: Golfed off (30?) bytes thanks to Laikoni! Also golfed some other misc. bytes.

Answer 15

Pyth, 47 45 44 40 Bytes

J.U-Zbm+*60hdedmmvkcd\:.z%"%d:%02d".DJ60

Takes the input separated by newlines.

Pyth had no time built-ins useful for this. I tried some fancy eval() stuff but apparantly Pyth can't eval stuff with * or any leading zeroes whatsoever. This got much longer than i hoped. Quite some bytes are spent on adding a leading zero to the output. At least I'm shorter than bash. Will add explanation if asked.

Try this!

alternative solution, 48 Bytes

J.U-Zbm+*60hdh_dmmvkcd\:.z
K%J60
s[/J60\:*<KT\0K

Answer 16

T-SQL, 238 bytes

CREATE PROCEDURE d @a time,@b time AS BEGIN DECLARE @d int DECLARE @s varchar(2) SET @d=datediff(s,@a,@b);SET @s=CAST(@d%3600/60 AS VARCHAR(3)) SELECT CAST(@d/3600 AS VARCHAR(3))+':'+(SELECT CASE WHEN LEN(@s)=1 THEN '0'+@s ELSE @s END)END

Usage:

EXEC d '00:55','01:00'

Seeing the PostGres example earlier I realised I hadn't seen many golfing attempts in SQL so I had a go at it in T-SQL. Now I know why you don't see much golfing in SQL :D

Answer 17

CJam, 34 33 25 bytes

Saved 8 bytes thanks to Martin Ender!

{r':/60b}2*\m60mds2Te[':\

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Explanation

{             e# Start of block
 r            e#  Read one time from input
 ':/          e#  Split on colons, gives [minutes seconds]
 60b          e#  Convert from base 60
}2*           e# Run this block 2 times
              e# At this point, we have the two times in seconds on the stack
\             e# Swap top elements
m             e# Subtract
60md          e# Divmod the result by 60, to convert back to minutes and seconds
s             e# Convert the seconds to a string
2Te[          e# Pad it to 2 characters by adding 0s to the left (T = 0)
':            e# Push a colon character
\             e# Swap top elements, bringing seconds back to the top

Answer 18

Python, 160 bytes

I am still new to code golf so if anyone has any suggestions, I would appreciate it.

a, b = input()
def z(x):
    x = x.split(":")
    return int(x[0])*60+int(x[1])
a, b = z(a),z(b)
s, m = b-a,0
while s >= 60:
    s -= 60
    m += 1
print(str(m)+":"+str(s))

Answer 19

T-SQL, 82 Bytes

select left(cast(dateadd(minute, datediff(S,'0:00','0:01')/60,114) as time(0)), 5)

Answer 20

REXX, 79 bytes

arg t q
say right(time(,f(q)-f(t),s),5)
f:return time(s,'00:'right(arg(1),5,0))

Answer 21

Pyth, 28

%"%d:%02d".Dh.+misMcd\:60Q60

Try it.

Explanation

                   cd\:      # lambda to split c on ":"
                 sM          # map to convert string to int
               mi      60Q   # convert from base-60 list to give seconds
             .+              # delta of the two seconds values
            h                # single-item list to int
          .D              60 # divmod by 60
%"%d:%02d"                   # format output

Answer 22

TXR Lisp, 101 bytes

$ txr -e '(awk (:let (s "%M:%S"))
               ((mf (time-parse s))
                (prn (time-string-local (- [f 1].(time-utc) [f 0].(time-utc)) s))))'
13:49 14:49 
01:00
0:13 1:47
01:34
5:01 5:59
00:58
6:00 6:00
00:00
6:00 5:00
59:00

Condensed: (awk(:let(s"%M:%S"))((mf(time-parse s))(prn(time-string-local(-[f 1].(time-utc)[f 0].(time-utc))s))))

Answer 23

Java 7, 164 bytes

String c(String a,String b){long s=x(b,1)-x(a,1)+(x(b,0)-x(a,0))*60,m=s%60;return(s/60)+":"+(m>9?m:"0"+m);}long x(String s,int i){return new Long(s.split(":")[i]);}

Explanation:

String c(String a, String b){       // Method with two String parameters and String return-type
  long s = x(b,1) - x(a,1)          //  Get difference in seconds from input times
           + (x(b,0) - x(a,0)*60,   //   plus the difference in minutes times 60 to get the seconds
    m = s%60;                       //  Temp variable of seconds after we've subtracted the minutes (used multiple times)
  return (s/60)                     //  Return minutes
    +":"                            //   plus ":"
    +(m>9?m:"0"+m);                 //   plus seconds (with a leading 0 if necessary)
}                                   // End of method

long x(String s,int i){             // Separate ethod with String and Integer parameters and long return-type
  return new Long(s.split(":")[i];  //  Return either minutes or seconds of String parameter based on the index
}                                   // End of method

Test code:

Try it here.

class M{
  String c(String a,String b){long s=x(b,1)-x(a,1)+(x(b,0)-x(a,0))*60,m=s%60;return(s/60)+":"+(m>9?m:"0"+m);}long x(String s,int i){return new Long(s.split(":")[i]);}

  public static void main(String[] a){
    M m = new M();
    System.out.println(m.c("0:00", "0:01"));
    System.out.println(m.c("0:55", "1:00"));
    System.out.println(m.c("1:45", "3:15"));
  }
}

Output:

0:01
0:05
1:30

Answer 24

Ruby, 91 bytes

require'time';t=Time;d=t.parse($*[1])-t.parse($*[0]);puts t.at(d.to_i).utc.strftime '%H:%M'

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Takes input from command line arguments.

Invocation:

ruby outatime.rb $A $B

Example:

ruby outatime.rb 1:45 3:15

Output:

01:30

Answer 25

PowerShell 47 Bytes

param($s,[timespan]$f)($f-$s).ToString("h\:mm")

Simple timespan math and coverting to hour and seconds string.

Answer 26

JavaScript, 88 bytes

a=>b=>{c=a.split`:`,d=b.split`:`;return +c[0]-d[0]-d[1]>c[1]?1:0+":"+(+c[1]+60-d[1])%60}

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Explanation:

Splits the inputs on the colon

c=a.split`:`,d=b.split`:`;

Converts string to int

+c[0]

Gets the minute value

+c[0]-d[0]-d[1]>c[1]?1:0

Gets the second value

(+c[1]+60-d[1])%60

Returns the string minutes:seconds

return +c[0]-d[0]-d[1]>c[1]?1:0+":"+(+c[1]+60-d[1])%60