From 0de7a49c127d7f4a9a0afaf6f3fa4e6ad75d0a43 Mon Sep 17 00:00:00 2001 From: "shuang.kou" Date: Fri, 13 Mar 2020 20:10:02 +0800 Subject: [PATCH] =?UTF-8?q?[fix]=E6=89=A9=E5=AE=B9=E9=97=AE=E9=A2=98?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- docs/java/collection/ArrayList-Grow.md | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/docs/java/collection/ArrayList-Grow.md b/docs/java/collection/ArrayList-Grow.md index ab56b802..0a758cca 100644 --- a/docs/java/collection/ArrayList-Grow.md +++ b/docs/java/collection/ArrayList-Grow.md @@ -145,7 +145,7 @@ } ``` -**int newCapacity = oldCapacity + (oldCapacity >> 1),所以 ArrayList 每次扩容之后容量都会变为原来的 1.5 倍！（JDK1.6版本以后）** JDk1.6版本时，扩容之后容量为 1.5 倍+1！详情请参考源码 +**int newCapacity = oldCapacity + (oldCapacity >> 1),所以 ArrayList 每次扩容之后容量都会变为原来的 1.5 倍左右（oldCapacity为偶数就是1.5倍，否则是1.5倍左右）！** 奇偶不同，比如 ：10+10/2 = 15, 33+33/2=49。如果是奇数的话会丢掉小数. > ">>"（移位运算符）：>>1 右移一位相当于除2，右移n位相当于除以 2 的 n 次方。这里 oldCapacity 明显右移了1位所以相当于oldCapacity /2。对于大数据的2进制运算,位移运算符比那些普通运算符的运算要快很多,因为程序仅仅移动一下而已,不去计算,这样提高了效率,节省了资源