{title}

{title} is a generation lesson about building only prefixes where open and close counts stay valid. It walks a decision tree, builds a partial answer, records complete valid answers, then backtracks to explore siblings.

Topic

Generation Problems

Pattern

Choice Tree Backtracking

Time

O(branches^depth)

Space

O(depth + output)

Call tree simulation

initial state

depth 0

choice

choose

choice

append

choice

record

choice

pop

Code Tracker

:::

1void backtrack(index, path) {

2 if (index == n) { save(path); return; }

3 for (choice : options(index)) {

4 path.push(choice);

5 backtrack(nextIndex, path);

6 path.pop();

7 }

Loading Lab...

Generate Parentheses

Generate Parentheses

{title}

{title}