Some binary bit operations

“>>” : Move right ：
Be careful ：Java Medium “>>” yes Count right ： Abandon the lowest position , The high bits are filled with sign bits ;
“>>>” yes Logical shift right ： Abandon the lowest position , High level 0 fill .
“|”： Or operation , One on both sides is 1 Namely 1, It can be equivalent to adding , Like binary （10|1） Namely （11）

Set of integers set An operation
When an integer set is marked , For example, in retrospect visited Flag array
vstd visit i ：vstd | (1 << i)
vstd Leave i ：vstd & ~(1 << i)
vstd It doesn't contain i : not vstd & (1 << i)

Combine ：A | B
intersection ：A & B
The complete ：(1 << n) - 1
Complement set ：((1 << n) - 1) ^ A
A subset of ：(A & B) == B
Judge whether it is 2 The power of ：A & (A - 1) == 0
The lowest 1 Turn into 0 ：n &= (n - 1)
The lowest 1：A & (-A), The lowest 1 It is generally recorded as lowbit(A) （ Get the lowest bit of a number 1 And later 0, Other bits become 0）（ The opposite number of a number is the number added after its bitwise negation 1）

Properties of XOR operation （^）：
XOR operation satisfies the exchange law and the combination law ;
The result of XOR operation of any integer and itself is equal to 0, namely x⊕x=0;
Any integer and 00 The result of XOR operation is equal to itself , namely x⊕0=0⊕x=x.