Golang: check to see if an item exists in an array... and then check if it exists between two items-CodePudding

This is hard to explain, I want to make sure a certain item does not exist between two other items. Here's some examples, "-1" is the item to watch:

1, 3, -1, 0, 1, 2 == BAD!

-1, 0, 3, -1, 1, 3 == BAD!

2, -1, -1, 4, 3, 1 == BAD!

1, -1, -1, -1, 2, 0 == BAD!

-1, -1, 0, -1, -1, -1 == BAD!

however...

if it's at the end or the beginning it's okay:

-1, 1, 2, 4, 0, -1 == OKAY!

0, 1, 2, -1, -1, -1 == OKAY!

-1, -1, -1, 2, 2, 1 == OKAY!

context: these are guitar chords and the "-1" is a muted string. I don't want the muted string in the middle of the chord because that's very hard to play

I hope that makes sense. If you know a better way to phrase it let me know and I'll change the title

edit: here's what I have so far because someone asked, but I honestly don't know where to start:

    for i := 0; i < len(c); i   {

//don't include if there's a -1 between two numbers
 if c[i] != 0 && c[i] != len(c) {

 }

}

CodePudding user response：

Try this. Change the problem statement. The slice of int is OKAY if the numbers that are not -1 are adjacent.

func check(input []int) bool {
    lastNonNeg := -1
    for i, n := range input {
        if n != -1 {
            // already encountered non negative and non adjacent (distance gt 1)
            if lastNonNeg != -1 && i-lastNonNeg > 1 {
                return false
            }
            // otherwise remember the index
            lastNonNeg = i
        }
    }
    return true
}

Input and output:

[1 3 -1 0 1 2] false
[-1 0 3 -1 1 3] false
[2 -1 -1 4 3 1] false
[1 -1 -1 -1 2 0] false
[-1 -1 0 -1 -1 -1] true
[-1 1 2 4 0 -1] true
[0 1 2 -1 -1 -1] true
[-1 -1 -1 2 2 1] true

Attention that input {-1, -1, -1, -1, -1, -1} is OKAY, but all mute chords is not difficult.

https://play.golang.org/p/Fzf8R4Seqan

CodePudding user response：

What if you put all values in a slice? numbers := strings.Split("1,2,3,4,5", ",")

then you can check where the particular thing is, and if it isn't the beginning, or the end, you might be good.