如果不传引用会复制整个vector吧
by iostream @ 2019-12-18 22:40:59
@[Froggy](/user/100285) 不传引用会把vector复制一遍传进来然后常数*2.
by WYXkk @ 2019-12-18 22:45:44
@[iostream](/user/13052) @[WYXkk](/user/130151) 谢谢大佬
by Froggy @ 2019-12-18 22:47:11