# Test case 1 - single node
{a}
{0}
# Test case 2 - standard tree
{a{b{c}{d{e}}}{f{g}{h{i{j}{k}}}}{l{m}}}
{0,9,12,10,11,3,8,4,5,7,6,1,2}
# Test case 3 - a path
{{{{{{{{{{{{{{{{{{{{}}}}}}}}}}}}}}}}}}}}
{0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19}
# Test case 4 - right-branch tree
{{}{{}{{}{{}{{}{}}}}}}
{0,10,1,9,2,8,3,7,4,6,5}
# Test case 5 - left-branch tree
{{{{{{}{}}{}}{}}{}}{}}
{0,2,4,6,8,10,9,7,5,3,1}
