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https://github.com/RussellChamp/advent-of-code-2021.git
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120 lines
2.3 KiB
Go
120 lines
2.3 KiB
Go
package bits
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import "fmt"
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func GetBitCount(val int) int {
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count := 0
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for val != 0 {
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count += val & 1
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val >>= 1
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}
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return count
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}
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// returns the number of matching bits in the two value's binary expression
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func MatchingOnBits(v1 int, v2 int) int {
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count := 0
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for v1 != 0 && v2 != 0 {
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if v1&1 == 1 && v2&1 == 1 {
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count += 1
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}
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v1 >>= 1
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v2 >>= 1
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}
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return count
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}
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func BitwiseAnd(v1 int, v2 int) int {
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val := 0
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for block := 1; v1 != 0 || v2 != 0; block <<= 1 {
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if v1&1 == 1 || v2&1 == 1 {
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val += block
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}
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if v1 > 0 {
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v1 >>= 1
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}
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if v2 > 0 {
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v2 >>= 1
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}
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}
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return val
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}
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func BitwiseAndA(a ...int) int {
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total := 0
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for _, i := range a {
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total = BitwiseAnd(total, i)
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}
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return total
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}
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func ByBitCount(size int) func(int) bool {
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return func(val int) bool { return GetBitCount(val) == size }
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}
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func ToInt(bits []bool) int {
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intVal := 0
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for idx := 0; idx < len(bits); idx++ {
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intVal = intVal << 1
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if bits[idx] {
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intVal += 1
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}
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}
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return intVal
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}
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func ToStr(bits []bool) string {
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str := ""
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for idx := 0; idx < len(bits); idx++ {
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if bits[idx] {
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str += "1"
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} else {
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str += "0"
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}
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}
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return str
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}
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func HexByteToBits(b byte) ([]bool, error) {
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// just do this manually because i can't be arsed
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switch b {
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case byte('0'):
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return []bool{false, false, false, false}, nil
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case byte('1'):
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return []bool{false, false, false, true}, nil
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case byte('2'):
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return []bool{false, false, true, false}, nil
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case byte('3'):
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return []bool{false, false, true, true}, nil
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case byte('4'):
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return []bool{false, true, false, false}, nil
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case byte('5'):
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return []bool{false, true, false, true}, nil
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case byte('6'):
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return []bool{false, true, true, false}, nil
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case byte('7'):
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return []bool{false, true, true, true}, nil
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case byte('8'):
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return []bool{true, false, false, false}, nil
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case byte('9'):
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return []bool{true, false, false, true}, nil
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case byte('A'):
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return []bool{true, false, true, false}, nil
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case byte('B'):
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return []bool{true, false, true, true}, nil
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case byte('C'):
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return []bool{true, true, false, false}, nil
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case byte('D'):
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return []bool{true, true, false, true}, nil
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case byte('E'):
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return []bool{true, true, true, false}, nil
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case byte('F'):
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return []bool{true, true, true, true}, nil
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default:
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return []bool{}, fmt.Errorf("read invalid byte")
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}
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}
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