The balanced connected subgraph problem

Sujoy Bhore, Sourav Chakraborty, Satyabrata Jana, Joseph S.B. Mitchell, Supantha Pandit, Sasanka Roy

Research output: Contribution to journalArticlepeer-review


The problem of computing induced subgraphs that satisfy some specified restrictions arises in various applications of graph algorithms and has been well studied. In this paper, we consider the following [Formula presented] ( [Formula presented] ) problem. The input is a graph G=(V,E), with each vertex in the set V having an assigned color, “ [Formula presented] ” or “ [Formula presented] ”. We seek a maximum-cardinality subset V⊆V of vertices that is [Formula presented] (having exactly |V|/2 red vertices and |V|/2 blue vertices), such that the subgraph induced by the vertex set V in G is connected. We show that the BCS problem is NP-hard, even for bipartite graphs G (with red/blue color assignment not necessarily being a proper 2-coloring). Further, we consider this problem on various graph classes, e.g., planar graphs, chordal graphs, trees, split graphs, bipartite graphs with a proper red/blue 2-coloring, and graphs with diameter 2. For each of these classes we either prove NP-hardness or design a polynomial time algorithm.

Original languageEnglish
Pages (from-to)111-120
Number of pages10
JournalDiscrete Applied Mathematics
StatePublished - 15 Oct 2022
Externally publishedYes


  • Balanced connected subgraph
  • Bipartite graphs
  • Chordal graphs
  • NP-hard
  • Planar graphs
  • Polynomial algorithms
  • Split graphs
  • Trees

ASJC Scopus subject areas

  • Discrete Mathematics and Combinatorics
  • Applied Mathematics


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