Multi-level map in Go

main.go

package main

var m = map[int]map[int]struct{}{
	1: {2: struct{}{}},
}

func main() {
	for _, item := range [][2]int{
		{1, 2},
		{1, 3},
		{2, 3},
		{3, 4},
	} {
		_, ok := m[item[0]][item[1]]
		println(ok)
	}
}