近似算法的若干基本概念 For every x E LI,the approximation ratio Ra(x)of as 为什么是两 Scost(A(x))Optu() RA()=max Optu(co(A 个选择？ For any nE N,we define the approximation ratio of A as RA(n)=max{RA()ELI(I)m}.近似算法的若干基本概念 为什么是两 个选择？