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Efficient way to calculate the minimum power of 2 that is greater than or equal to the given integer
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| package main | |
| import ( | |
| "fmt" | |
| "math/bits" | |
| ) | |
| // BitCeil returns the minimum power of 2 that is greater than or equal to x. | |
| // It returns 1 when x is 0. | |
| func BitCeil(x uint) uint { | |
| if x < 2 { | |
| return 1 | |
| } | |
| return 1 << (bits.UintSize - bits.LeadingZeros(x-1)) | |
| } | |
| func main() { | |
| for i := range 30 { | |
| fmt.Printf("i = %d, BitCeil(i) = %d\n", i, BitCeil(uint(i))) | |
| } | |
| } |
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