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  1. // Copyright 2017-2018 DERO Project. All rights reserved.
  2. // Use of this source code in any form is governed by RESEARCH license.
  3. // license can be found in the LICENSE file.
  4. // GPG: 0F39 E425 8C65 3947 702A 8234 08B2 0360 A03A 9DE8
  5. //
  6. //
  7. // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
  8. // EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  9. // MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
  10. // THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  11. // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  12. // PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  13. // INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  14. // STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
  15. // THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  16. package blockchain
  17. import "sort"
  18. type uint64arr []uint64
  19. func (a uint64arr) Len() int { return len(a) }
  20. func (a uint64arr) Swap(i, j int) { a[i], a[j] = a[j], a[i] }
  21. func (a uint64arr) Less(i, j int) bool { return a[i] < a[j] }
  22. // Median gets the median number in a slice of uint64 numbers
  23. // this function is used in so many checks that it should have unit tests for sure
  24. // NOTE: it will the input array
  25. func Median(inputs []uint64) (median uint64) {
  26. // Start by sorting
  27. sort.Sort(uint64arr(inputs))
  28. // No math is needed if there are no numbers
  29. // For even numbers we add the two middle numbers
  30. // and divide by two using the mean function above
  31. // For odd numbers we just use the middle number
  32. l := len(inputs)
  33. if l == 0 {
  34. return 0
  35. } else if l%2 == 0 {
  36. median = (inputs[(l/2)-1] + inputs[(l/2)]) / 2
  37. } else {
  38. median = inputs[l/2]
  39. }
  40. return median
  41. }