问题
What is the time complexity of * Arithmetic left shift* / * Arithmetic right shift* operators of a n bit operand for example doing x = y << 2; whow much time will it take ?
回答1:
Complexity, with the O(…) notation, is an asymptotic characterization of the time an algorithm takes when the input size becomes larger and larger. It is meaningless for algorithms that can take only a finite number of inputs. << can take 2^32 * 32 different inputs, hence a finite number of inputs, therefore it is constant-time (O(1)).
来源：https://stackoverflow.com/questions/18470210/arithmetic-left-shift-time-complexity