NP难问题 NP hard problem

NP困难 NP-hard

NP难解问题 NP-problem

NP难度 NP hard ; non-deterministic polynomial hard ; NP-hardness ; NP difficulty

np难题 np-hard ; np difficult problem

NP难度问题 NP-hard problem

np难的 np-hard ; known as np-hard

np难度问题 np hard problems