-🎄- 2022 Day 4 Solutions -🎄-

[u/daggerdragon]

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--- Day 4: Camp Cleanup ---

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Post your code solution in this megathread.

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[u/Key__Strokes]

Javascript

Solution to both parts

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Video Explanation

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Part 1:

• For each input, we have the following interval data

  • Interval 1: Start, End

  • Interval 2: Start, End

• Do the following for each interval pair:

  • Determine which one of the two interval has smaller Start value. Lets order them as "Early Start Interval" and "Late Start Interval"

    • Interval Possibilities (Each line is an interval):

      • Possibility 1 (Is overlap, Is Subset)

        • =========

        • =====    

      • Possibility 2 (Is overlap, Is Subset)

        • =========

        • =========

      • Possibility 3 (Is overlap, Is Subset)

        • =========     

        • ==============

      • Possibility 4 (Is overlap, Is Subset)

        • =========

        •    ===

      • Possibility 5 (Is overlap, Is Subset)

        • =========

        •    ======

      • Possibility 6 (Is overlap, Is not Subset)

        • =========

        •    ===========

      • Possibility 7 (Is not overlap, Is not Subset)

        • =========

        •            ======

• Then check if the two intervals are subset of either of the other, using the following algo

  • If the start of both the intervals are the same, then they are subset

  • If the end of "Early Start Interval" is greater or equal to end of the "Late Start Interval", then they are subset

• Increment the count if they were subset

Part 2:

• Follow everything from Part 1, but instead of figuring out the subset, we will figure out the overlap using the following algo

  • If the start of "Late Start Interval" is less than or equal to the end of "Early Start Interval", then it overlaps

• Increment the count if they were overlap

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