Code
The highlighted line runs next. The pill shows the live values in the running call.
Cost
Work done so far, and how the two solutions compare
Tree and result
Each level becomes one row of res
The highlighted line runs next. The pill shows the live values in the running call.
Work done so far, and how the two solutions compare
Each level becomes one row of res
Keyboard: ← → step, Space play or pause. Enter the tree in level order with null for missing children, as LeetCode does (up to 15 nodes, 5 levels, values −1000 to 1000).