Journal of the Operations Research Society of China ›› 2026, Vol. 14 ›› Issue (2): 397-412.doi: 10.1007/s40305-024-00539-y

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Approximation Algorithms for k-Submodular Maximization Subject to a Knapsack Constraint

Hao Xiao, Qian Liu, Yang Zhou, Min Li   

  1. School of Mathematics and Statistics, Shandong Normal University, Jinan 250358, Shandong, China
  • Received:2023-10-10 Revised:2024-01-03 Online:2026-06-30 Published:2026-07-06
  • Contact: Min Li E-mail:liminemily@sdnu.edu.cn
  • Supported by:
    This research was supported by the Natural Science Foundation of Shandong Province of China (Nos. ZR2020MA029 and ZR2021MA100) and the National Natural Science Foundation of China (No. 12001335).

Abstract: In this paper, we study the problem of maximizing $k$-submodular functions subject to a knapsack constraint. For monotone objective functions, we present a $\frac{1}{2}\left(1-\mathrm{e}^{-2}\right) \approx$ 0.432 greedy approximation algorithm, improving the previous best-known ratio $\frac{1}{2}(1- \left.\mathrm{e}^{-1}\right) \approx 0.316$. We also consider the non-monotone knapsack problem and provide two algorithms. The first is a greedy-type combinatorial algorithm with approximation ratio $\frac{1}{3}\left(1-\mathrm{e}^{-3}\right) \approx 0.317$, while the second is a multilinear-extension-based algorithm with approximation ratio $\frac{1}{3}-\varepsilon$, where $\varepsilon>0$.

Key words: k-submodular, Knapsack, Approximation algorithm

CLC Number: