Leetcode Note: Go - Find All K Distant Indices in an Array

func findKDistantIndices(nums []int, key int, k int) []int {
    var res []int
    resMap := make(map[int]struct{})

    for i, v := range nums {
        if v == key {         
            for j := i - k; j <= i + k; j++ {
                if j < 0 || j >= len(nums) {
                    continue
                }

                if _, ok := resMap[j]; !ok {
                    resMap[j] = struct{}{}
                    res = append(res, j)   
                }
            }
        }
    }
    
    return res
}