大 O，您如何计算 / 近似？

algorithm optimization complexity-theory big-o performance

如何找到算法的时间复杂度

algorithm time-complexity complexity-theory

NP，NP-Complete 和 NP-Hard 有什么区别？

computer-science complexity-theory np np-complete np-hard

“Big O” 符号的简单英语解释是什么？

algorithm complexity-theory computer-science big-o time-complexity