child.child[getBitFromAddr(n.prefix.Addr(), pos)] = n
			return false
		}

		// Case 2: existing node has the same mask but different base address
		// add common ancestor and branch on it
		ancestor := findAncestor(prefix, n.prefix)
		link := &node[T]{
			prefix: ancestor,
		}
		pos := parent.prefix.Bits() + 1
		parent.child[getBitFromAddr(ancestor.Addr(), pos)] = link

			ip:   netip.MustParseAddr("2001:db8::ff00:42:8329"),
			pos:  128,
			want: 1,
		},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			if got := getBitFromAddr(tt.ip, tt.pos); got != tt.want {
				t.Errorf("getBitFromAddr() = %v, want %v", got, tt.want)
			}
		})
	}
}

func TestShortestPrefix(t *testing.T) {
	r := New[int]()

	keys := []string{
		"10.0.0.0/8",