4: Add solution for Rust track exercise "Leap".

Dependencies

• [2] XN7GOFDN 3: Add Rust track exercise "Leap".

Change contents

• replacement in rust/leap/tests/leap.rs at line 2
  [2.122]→[2.122:174](∅→∅)
  − assert_eq!(leap::is_leap_year(year), expected);
  [2.122]

  [2.174]
  + assert_eq!(leap::is_leap_year(year), expected);
• replacement in rust/leap/tests/leap.rs at line 7
  [2.233]→[2.233:273](∅→∅)
  − process_leapyear_case(2015, false);
  [2.233]

  [2.273]
  + process_leapyear_case(2015, false);
• replacement in rust/leap/tests/leap.rs at line 13
  [2.360]→[2.360:400](∅→∅)
  − process_leapyear_case(1970, false);
  [2.360]

  [2.400]
  + process_leapyear_case(1970, false);
• replacement in rust/leap/tests/leap.rs at line 19
  [2.484]→[2.484:523](∅→∅)
  − process_leapyear_case(1996, true);
  [2.484]

  [2.523]
  + process_leapyear_case(1996, true);
• replacement in rust/leap/tests/leap.rs at line 25
  [2.603]→[2.603:642](∅→∅)
  − process_leapyear_case(1960, true);
  [2.603]

  [2.642]
  + process_leapyear_case(1960, true);
• replacement in rust/leap/tests/leap.rs at line 31
  [2.730]→[2.730:770](∅→∅)
  − process_leapyear_case(2100, false);
  [2.730]

  [2.770]
  + process_leapyear_case(2100, false);
• replacement in rust/leap/tests/leap.rs at line 37
  [2.863]→[2.863:903](∅→∅)
  − process_leapyear_case(1900, false);
  [2.863]

  [2.903]
  + process_leapyear_case(1900, false);
• replacement in rust/leap/tests/leap.rs at line 43
  [2.968]→[2.968:1007](∅→∅)
  − process_leapyear_case(2000, true);
  [2.968]

  [2.1007]
  + process_leapyear_case(2000, true);
• replacement in rust/leap/tests/leap.rs at line 49
  [2.1098]→[2.1098:1137](∅→∅)
  − process_leapyear_case(2400, true);
  [2.1098]

  [2.1137]
  + process_leapyear_case(2400, true);
• replacement in rust/leap/tests/leap.rs at line 55
  [2.1225]→[2.1225:1265](∅→∅)
  − process_leapyear_case(1800, false);
  [2.1225]

  [2.1265]
  + process_leapyear_case(1800, false);
• replacement in rust/leap/tests/leap.rs at line 61
  [2.1311]→[2.1311:1351](∅→∅)
  − process_leapyear_case(1997, false);
  [2.1311]

  [2.1351]
  + process_leapyear_case(1997, false);
• replacement in rust/leap/tests/leap.rs at line 67
  [2.1396]→[2.1396:1585](∅→∅)
  − process_leapyear_case(1, false);

  − process_leapyear_case(4, true);

  − process_leapyear_case(100, false);

  − process_leapyear_case(400, true);

  − process_leapyear_case(900, false);
  [2.1396]

  [2.1585]
  + process_leapyear_case(1, false);

  + process_leapyear_case(4, true);

  + process_leapyear_case(100, false);

  + process_leapyear_case(400, true);

  + process_leapyear_case(900, false);
• replacement in rust/leap/tests/leap.rs at line 77
  [2.1626]→[2.1626:1746](∅→∅)
  − process_leapyear_case(1700, false);

  − process_leapyear_case(1800, false);

  − process_leapyear_case(1900, false);
  [2.1626]

  [2.1746]
  + process_leapyear_case(1700, false);

  + process_leapyear_case(1800, false);

  + process_leapyear_case(1900, false);
• replacement in rust/leap/tests/leap.rs at line 85
  [2.1801]→[2.1801:1918](∅→∅)
  − process_leapyear_case(1600, true);

  − process_leapyear_case(2000, true);

  − process_leapyear_case(2400, true);
  [2.1801]

  [2.1918]
  + process_leapyear_case(1600, true);

  + process_leapyear_case(2000, true);

  + process_leapyear_case(2400, true);
• replacement in rust/leap/tests/leap.rs at line 93
  [2.1970]→[2.1970:2108](∅→∅)
  − let incorrect_years = (1600..1700)

  − .filter(|&year| leap::is_leap_year(year) != (year % 4 == 0))

  − .collect::<Vec<_>>();
  [2.1970]

  [2.2108]
  + let incorrect_years = (1600..1700)

  + .filter(|&year| leap::is_leap_year(year) != (year % 4 == 0))

  + .collect::<Vec<_>>();
• replacement in rust/leap/tests/leap.rs at line 97
  [2.2109]→[2.2109:2221](∅→∅)
  − if !incorrect_years.is_empty() {

  − panic!("incorrect result for years: {:?}", incorrect_years);

  − }
  [2.2109]

  [2.2221]
  + if !incorrect_years.is_empty() {

  + panic!("incorrect result for years: {:?}", incorrect_years);

  + }
• edit in rust/leap/src/lib.rs at line 1
  [2.2271]

  [2.2272]
  + /*

  + Info about year lengths: https://en.wikipedia.org/wiki/Year#Summary

  + Mean tropical year is about 365.24219: http://adsabs.harvard.edu/pdf/1999A%26A...341..318M

  + The reason for Gregorian Calendar rules for leap days: https://blog.plover.com/calendar/leapday.html

  + */
• replacement in rust/leap/src/lib.rs at line 7
  [2.2313]→[2.2313:2367](∅→∅)
  − unimplemented!("true if {} is a leap year", year)
  [2.2313]

  [2.2367]
  + // Check divisibility. Panics if `b` is `0`.

  + fn a(a: u64, b: u64) -> bool {

  + a % b == 0

  + }

  +

  + a(year, 80000) || !a(year, 3200) && a(year, 400) || !a(year, 100) && a(year, 4)