# Test case 1 - single node
{a}
{{}}
# Test case 2 - standard tree
{a{b{c}{d{e}}}{f{g}{h{i{j}{k}}}}{l{m}}}
{{1,5,11},{2,3},{},{4},{},{6,7},{},{8},{9,10},{},{},{12},{}}
# Test case 3 - a path
{{{{{{{{{{{{{{{{{{{{}}}}}}}}}}}}}}}}}}}}
{{1},{2},{3},{4},{5},{6},{7},{8},{9},{10},{11},{12},{13},{14},{15},{16},{17},{18},{19},{}}
# Test case 4 - right-branch tree
{{}{{}{{}{{}{{}{}}}}}}
{{1,2},{},{3,4},{},{5,6},{},{7,8},{},{9,10},{},{}}
# Test case 5 - left-branch tree
{{{{{{}{}}{}}{}}{}}{}}
{{1,10},{2,9},{3,8},{4,7},{5,6},{},{},{},{},{},{}}
