palindrome: use slices in the concurrent version too. The single thread version is so fast now, that using channels makes this one slower

Dependencies

• [2] L5UJYVXW palindrome: Use string slice instead of concatenating, this makes the code WAY faster
• [3] ZQFONDI4 Add simple version
• [4] O64GEJAP palindrome: do not report one char long palindromes
• [5] AUM6AXH7 It is enough to check only half of the string because of symmetry
• [6] VUXCDW3L palindrome: move to palindrome package
• [7] MCHVA5DY Palindrome initial import

Change contents

• replacement in snippets/palindrome/palindrome.go at line 35
  [3.264]→[3.534:549](∅→∅),[2.242]→[3.534:549](∅→∅),[3.727]→[3.534:549](∅→∅),[3.534]→[3.534:549](∅→∅)
  − longest := ""
  [2.242]

  [3.549]
  + var longest string
• replacement in snippets/palindrome/palindrome.go at line 40
  [3.628]→[3.628:662](∅→∅)
  − go pal_worker(str, k, results)
  [3.628]

  [3.662]
  + go palWorker(str, k, results)
• replacement in snippets/palindrome/palindrome.go at line 59
  [3.876]→[3.876:1091](∅→∅)
  − func pal_worker(str string, k int, result chan<- string) {

  − longest := string(str[k])

  − for i := 1; true; i++ {

  − // avoid overrun or underrun

  − if k-i < 0 || k+i > len(str)-1 {

  − break

  − }

  − // two identical bytes
  [3.876]

  [3.1091]
  + func palWorker(str string, k int, result chan<- string) {

  + var longest string

  + for i := 1; k-i > -1 && k+i < len(str); i++ {
• replacement in snippets/palindrome/palindrome.go at line 63
  [3.1119]→[3.1119:1178](∅→∅)
  − longest = string(str[k-i]) + longest + string(str[k+i])
  [3.1119]

  [3.1178]
  + longest = str[k-i : k+i+1]
• edit in snippets/palindrome/palindrome.go at line 67
  [3.1202]→[3.1202:1270](∅→∅),[3.1270]→[3.55:123](∅→∅)
  − }

  − //fmt.Fprintf(os.Stderr, "Worker(%d) result: %s\n", k, longest)

  − if len(longest) > 1 {

  − result <- longest

  − } else {

  − result <- ""
• edit in snippets/palindrome/palindrome.go at line 68
  [3.126]

  [3.1289]
  + result <- longest