  Full connectivity of qubits is necessary for most quantum algorithms, which
is difficult to directly implement on Noisy Intermediate-Scale Quantum
processors. However, inserting swap gate to enable the two-qubit gates between
uncoupled qubits significantly decreases the computation result fidelity. To
this end, we propose a Special-Purpose Quantum Processor Design method that can
design suitable structures for different quantum algorithms. Our method extends
the processor structure from two-dimensional lattice graph to general planar
graph and arranges the physical couplers according to the two-qubit gate
distribution between the logical qubits of the quantum algorithm and the
physical constraints. Experimental results show that our design methodology,
compared with other methods, could reduce the number of extra swap gates per
two-qubit gate by at least 104.2% on average. Also, our method's advantage over
other methods becomes more obvious as the depth and qubit number increase. The
result reveals that our method is competitive in improving computation result
fidelity and it has the potential to demonstrate quantum advantage under the
technical conditions.
