package A

import "math/bits"

func reverseBits(n int) int {
	res := 0
	for i := 0; i < 32; i++ {
		res = (res << 1) | (n & 1)
		n >>= 1
	}
	return res
}

func reverseBits2(n int) int {
	return int(bits.Reverse32((uint32(n))))
}