approximation algo-rithm的用法和样例：
例句
- An approximation algorithm is presented for minimizing a nondecreasing supermodular set function, and its performance guarantee is probed.
摘要给出了求解一类上模集函数最小值问题的一种近似算法，并讨论了所给算法的性能保证。 - Then, a linear time approximation algorithm was developed, which also provided a solution with the same worst case approximation bounds as LP-approximation.
然后设计了一个非常简单有用的可以和廿近似算法得到一样好的近似解的线性时间近似算法。
