C#•2y ago

Get longest consecutive date 'streak' [Answered]

I'm trying to figure out a nice way of getting a date-streak from a list of objects which will have activities on them. The premise to the problem is, each user records their 'excercise' which can be multiples per day. I don't care about anything other than some acceptence criteria (namely, duration of the exercise) but I can group these effectively into some structure I assume of:

 [date] : [true/false]

 [date] : [true/false]

This would indicate if the user has completed an activity on that date. Where I'm struggling is to then calculate the streak of dates (the largest streak) in that full list, ie:

1st : true
2nd : false
3rd : true
4th : true
5th : false
6th : true
7th : false

1st : true
2nd : false
3rd : true
4th : true
5th : false
6th : true
7th : false

Here the users top 'streak' is going to be 2, as completed on the 3rd and 4th

14 Replies

Becquerel•2y ago

this sounds very similar to the classic 'gaps and islands' problem often seen in SQL

Bread•2y ago

I may be structuring the data wrong initially and is not gospel

Becquerel•2y ago

a manual way to do it would be to loop through the entire collection with a 'currentStreak' and 'largestStreak' counters

Xymanek•2y ago

int maxStreak = 0;
int currentStreak = 0;

foreach (bool status in days)
{
  if (status)
  {
    currentStreak++;
    if (currentStreak > maxStreak) maxStreak = currentStreak;
  }
  else
  {
    currentStreak = 0;
  }
}

int maxStreak = 0;
int currentStreak = 0;

foreach (bool status in days)
{
  if (status)
  {
    currentStreak++;
    if (currentStreak > maxStreak) maxStreak = currentStreak;
  }
  else
  {
    currentStreak = 0;
  }
}

Becquerel•2y ago

increment current streak if current item is true, increment largestStreak if it's larger yeah, like that

Bread•2y ago

I won't have access to SQL unfortunately, so that looks like a good idea

Xymanek•2y ago

this would be definitely more complicated in SQL

Becquerel•2y ago

yeah, i'm not suggesting to use SQL, just giving you a name you can google to look around for other ideas if necessary

Bread•2y ago

yeah appreciate that, never heard it before so some nice reading Thanks folks!

Becquerel•2y ago

you can use '/close' to end the thread now

Bread•2y ago

let me steal the code first then I will

Accord•2y ago

✅ This post has been marked as answered!

Bread•2y ago

Oh it doesn't delete? awesome

Accord•2y ago

✅ This post has been marked as answered!

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Get longest consecutive date 'streak' [Answered]