Valid Arrangement of Pairs — LeetCode 2097 Python Solution
HardDepth-First SearchGraphEulerian Circuit
- Problem
- #2097
- Pattern
- Depth-First Search
- Reading time
- 2 min
- Source
- leetcode.com
The problem
You are given a 0-indexed 2D integer array pairs where pairs[i] = [starti, endi]. An arrangement of pairs is valid if for every index i where 1 <= i < pairs.length, we have endi-1 == starti.
Example
- Input
- pairs = [[5,1],[4,5],[11,9],[9,4]]
- Output
- [[11,9],[9,4],[4,5],[5,1]]
- Explanation
- This is a valid arrangement since endi-1 always equals starti.
Complexity
| Measure | Complexity |
|---|---|
| Time | O(V+E) |
| Space | O(V) auxiliary |
Pattern: Depth-First Search
Follow one path to its end before trying the next — the default way to explore a graph. LeetCode 2097. Valid Arrangement of Pairs is filed here on both counts: the reference solution below belongs to the algorithm family this hub collects, and LeetCode tags it Depth-First Search and Graph.
The depth-first search guide has the Python template for the pattern and the 366 LeetCode problems that use it.
Related problems
Frequently asked questions
- How hard is LeetCode 2097. Valid Arrangement of Pairs?
- LeetCode 2097. Valid Arrangement of Pairs is rated Hard on LeetCode.
- What is the time complexity of LeetCode 2097. Valid Arrangement of Pairs?
- The Python solution on this page runs in O(V+E).
- What is the space complexity of LeetCode 2097. Valid Arrangement of Pairs?
- The Python solution on this page uses O(V) auxiliary space.
- What topics does LeetCode 2097. Valid Arrangement of Pairs cover?
- LeetCode 2097. Valid Arrangement of Pairs is tagged Depth-First Search, Graph and Eulerian Circuit on LeetCode.