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Summary of bit operation skills (continuous update...)
1. Number 3 that only appears once
Using XOR operation can help us eliminate numbers that appear twice
x & (-x) is the rightmost 1 in the reserved bits and the other 1 is set to 0.
Two, 191. The number of bits 1
(When x is not 0) x & (x-1) is a method to change the rightmost 1 to 0 and keep the rest of the bits unchanged.
In addition:
Change the first 0 from the right to 1: x or (x+1)
Turn the consecutive 1s on the right into 0: x and (x+1)
Change the consecutive 0s on the right to 1: x or (x-1)
3. Set a certain position to 0 or set it to 1 or negate it
Set the i-th position of x (counted from the right) to 1, x=x | (1<<(i-1))
Set the i position of x (counting from the right) to 0, x=x & !(1<<(i-1))
Invert the i-th position of x (counting from the right), x=x ^ (1<<(i-1))