Learn
Practice
Interview
Resources
Newsletter
F
Toggle theme
0
F
0
Toggle menu
Animations
← Back to All Animations
Sum of Left Leaves
Bookmark
Recursive DFS
Iterative BFS
Iterative Stack
Input
Example 1 (sum=24)
Example 2 (sum=4)
Right Leaves Don't Count (sum=8)
Single Node (sum=0)
Custom
tree
=
[3, 9, 20, null, null, 15, 7]
3
9
20
15
7
sum = 0
leaves
sum every
left leaf
via recursion
3
9
20
15
7
sum = 0
leaves
sum every
left leaf
via recursion
3
9
20
15
7
sum = 0
leaves
visit
3
(root)
3
9
20
15
7
sum = 0
leaves
3
is internal: recurse left + right
3
9
20
15
7
sum = 9
leaves
9
left leaf
9
: sum = 9
3
9
20
15
7
sum = 9
leaves
9
visit
20
(right child)
3
9
20
15
7
sum = 9
leaves
9
20
is internal: recurse left + right
3
9
20
15
7
sum = 9
leaves
9
visit
15
(left child)
3
9
20
15
7
sum = 24
leaves
9
15
visit
7
(right child)
3
9
20
15
7
sum = 24
leaves
9
15
7
is a leaf but not a left child:
+0
3
9
20
15
7
sum = 24
leaves
9
15
return 24
algo
master
.
io
Step:
Start: sum every left leaf with recursion
0 / 11
Input
Example 1 (sum=24)
Example 2 (sum=4)
Right Leaves Don't Count (sum=8)
Single Node (sum=0)
Custom
tree
=
[3, 9, 20, null, null, 15, 7]
0 / 11
algo
master
.
io
Step:
Start: sum every left leaf with recursion
