Leetcode 1272

What This Code Is Doing:

We make a new resulting array and then loop through intervals.

What we need to know for the following if and else statements is when the code loops through intervals, we get interval per iteration. interval is in the format [start, end]. Also, the constraints say -10^9 <= start < end <= 10^9, so we can see that start and end are never on the exact same location and the start is always lesser than end.

The if and else statments are as follows:

When we do the if statment: if interval[0] < toBeRemoved[0] && toBeRemoved[1] < interval[1] { we are checking whether the start of interval is smaller than the start of toBeRemoved and the end of interval is greater than the end of toBeRemoved, like in the following image: (Note: interval is green and toBeRemoved is red) The start of interval is smaller than the start of toBeRemoved, and the end of interval is greater than the end of toBeRemoved.
The first else if statment is else if interval[0] < toBeRemoved[0] && interval[1] > toBeRemoved[0] && interval[1] <= toBeRemoved[1] {. It is for if the interception of interval and toBeRemoved is on the right of toBeRemoved, this can be shown with an image: This is for if interval’s start is smaller than toBeRemoved’s start, intervals’s end is smaller than toBeRemoved’s end, and interval’s end is greater than toBeRemoved’s start.
The next else if is else if interval[0] >= toBeRemoved[0] && interval[0] < toBeRemoved[1] && interval[1] > toBeRemoved[1] {. Is for the same thing as the first else if except it is on the other side of toBeRemoved. This can be shown using an image:
The next else if is else if interval[0] >= toBeRemoved[0] && interval[0] < toBeRemoved[1] && interval[1] <= toBeRemoved[1] && interval[1] > toBeRemoved[0] {. This is for if the start of interval is greater than the start of toBeRemoved and the end of interval is smaller than end of toBeRemoved. This can be shown using an image:
And last but not least our else. This is for if there is no overlap of interval and toBeRemoved. This can be shown using an image:

That is all there is to the code, thank you for reading.

The Code:

func removeInterval(intervals [][]int, toBeRemoved []int) [][]int {
    res := [][]int{}
    for _, interval := range intervals {
        if interval[0] < toBeRemoved[0] && toBeRemoved[1] < interval[1] {
        
            res = append(res, []int{interval[0], toBeRemoved[0]}, 
            []int{toBeRemoved[1], interval[1]})
            
        } else if interval[0] < toBeRemoved[0] && interval[1] > toBeRemoved[0]
        && interval[1] <= toBeRemoved[1] {
        
            res = append(res, []int{interval[0], toBeRemoved[0]})
            
        } else if interval[0] >= toBeRemoved[0] && interval[0] < toBeRemoved[1]
        && interval[1] > toBeRemoved[1] {
        
            res = append(res, []int{toBeRemoved[1], interval[1]})
            
        } else if interval[0] >= toBeRemoved[0] && interval[0] < toBeRemoved[1]
        && interval[1] <= toBeRemoved[1] && interval[1] > toBeRemoved[0] {
        
            continue
            
        } else {
            res = append(res, interval)
        }
    }
    return res
}