An algorithm with a delay of $\mathcal{O}(k\Delta)$ for enumerating connected induced subgraphs of size $k$

TL;DR

This paper introduces an efficient algorithm for enumerating all connected induced subgraphs of a specific size in a graph, achieving a significantly improved delay bound compared to previous methods.

Contribution

The paper presents a novel algorithm with a delay of O(kΔ) for enumerating connected induced subgraphs, improving upon the previous O(k^2Δ) delay bound.

Findings

Achieves a delay of O(kΔ) for enumeration

Requires only O(|V| + |E|) preprocessing time

Outperforms previous delay bounds in the literature

Abstract

The problem of enumerating connected subgraphs of a given size in a graph has been extensively studied in recent years. In this paper, we propose an algorithm with a delay of $O(k\Delta)$ for enumerating all connected induced subgraphs of size $k$ in an undirected graph $G=(V, E)$, where $k$ and $\Delta$ are respectively the size of subgraphs and the maximum degree of $G$. The algorithm requires a preprocessing step of $O(|V| + |E|)$ time to compute a depth-first search traversal order. The proposed algorithm improves upon the current best delay bound $O(k^2\Delta)$ for the connected induced subgraph enumeration problem in the literature.