是一个渐近的算法运行时的复杂性θ(n)总是比类似的算法更快的运行时和运行时的复杂性θ(n ^ 2)?

If so can you provide explicit examples? I understand that an algorithm like Quicksort can have O(n log n) expected running time, but O(n^2) in the worse case. I presume that if the same principle of expected/worst case applies to theta, then the above question could be false. Understanding how theta works will help me to understand the relationship between theta and big-O.If so can you provide explicit examples? I unde