Direct Application of QAOA Algorithm to PUBO Problem

Previously, the approach to solving the PUBO (multiple unconstrained binary optimization) was to transform it into the QUBO (Quadratic Unconstrained Binary Optimization) via variable substitution. Variable substitution is bound to introduce new variables, and when using the QAOA algorithm for solution, it also implies that inevitably more controllable qubits are required. However, this paper will explore how to directly apply the QAOA algorithm to the PUBO problem without converting the PUBO to QUBO, thereby reducing the utilization of qubits.