June 2018 Update

Task/Five-weekends/Factor/five-weekends.factor

@@ -0,0 +1,17 @@
+USING: calendar calendar.format formatting fry io kernel math
+sequences ;
+IN: rosetta-code.five-weekends
+
+: timestamps>my ( months -- )
+   [ { MONTH bl YYYY nl } formatted 2drop ] each ;
+
+: month-range ( start-year #months -- seq )
+    '[ _ <year> _ <iota> ] call [ months time+ ] with map ;
+
+: find-five-weekend-months ( months -- months' )
+    [ [ friday? ] [ days-in-month ] bi 31 = and ] filter ;
+
+1900 12 201 * month-range find-five-weekend-months
+[ length "%d five-weekend months found.\n" printf ]
+[ 5 head  timestamps>my "..." print               ]
+[ 5 tail* timestamps>my                           ] tri

Task/Five-weekends/Julia/five-weekends.julia

@@ -1,26 +1,21 @@
-isdefined(:Date) || using Dates
+isweekend(dt::Date) = Dates.dayofweek(dt) ∈ (Dates.Friday, Dates.Saturday, Dates.Sunday)
 
-const wday = Dates.Fri
-const lo = 1900
-const hi = 2100
-const showres = 5
-
-mfive = recur(Date(lo, 1):Month(1):Date(hi, 12)) do m
-    Dates.daysinmonth(m) == 31 && Dates.dayofweek(m) == wday
+function hasfiveweekend(month::Integer, year::Integer)
+    dmin = Date(year, month, 1)
+    dmax = dmin + Dates.Day(Dates.daysinmonth(dmin) - 1)
+    return count(isweekend, dmin:dmax) ≥ 15
 end
 
-println("Considering the years from ", lo, " to ", hi, ".\n")
-println("There are ", length(mfive), " months having 5 3-day weekends.")
+months = collect((y, m) for y in 1900:2100, m in 1:12 if hasfiveweekend(m, y))
 
-println("The first ", showres, " such months are:")
-for m in mfive[1:showres]
-    println("    ", Dates.monthname(m), " ", Dates.year(m))
-end
+println("Number of months with 5 full-weekends: $(length(months))")
+println("First five such months:")
+for (y, m) in months[1:5] println(" - $y-$m") end
+println("Last five such months:")
+for (y, m) in months[end-4:end] println(" - $y-$m") end
 
-println("\nThe last ", showres, " such months are:")
-for m in mfive[end-showres+1:end]
-    println("    ", Dates.monthname(m), " ", Dates.year(m))
-end
+# extra credit
+yrs = getindex.(months, 1)
+nyrs = 2100 - 1899 - length(unique(yrs))
 
-print("\nThere are ", length(filter(y -> !(y in year(mfive)), lo:hi)))
-println(" years that have no such months.")
+println("Number of year with not one 5-full-weekend month: $nyrs")

Task/Five-weekends/Maple/five-weekends.maple

@@ -0,0 +1,17 @@
+five_weekends:= proc()
+	local i, month, count;
+	#Only months with 31 days can possibly satisfy the condition
+	local long_months := [1,3,5,7,8,10,12];
+	local months := ["January","February","March","April","May","June","July","August","September","October","November","December"];
+	count := 0;
+	for i from 1900 to 2100 by 1 do
+		for month in long_months do
+			if Calendar:-DayOfWeek(Date(i, month, 1)) = 6 then
+				printf("%d-%s\n", i, months[month]);
+				count++;
+			end if;
+		end do;
+	end do;
+	printf("%d months have five full weekends.\n", count);
+end proc;
+five_weekends();

Task/Five-weekends/Stata/five-weekends.stata

@@ -0,0 +1,30 @@
+clear
+set obs `=tm(2101m1)-tm(1900m1)'
+gen month=tm(1900m1)+_n-1
+format %tm month
+gen day=dofm(month)
+keep if dofm(month+1)-day==31 & dow(day)==5
+drop day
+
+count
+  201
+
+list in f/5, noobs noheader
+
+  +--------+
+  | 1901m3 |
+  | 1902m8 |
+  | 1903m5 |
+  | 1904m1 |
+  | 1904m7 |
+  +--------+
+
+list in -5/l, noobs noheader
+
+  +---------+
+  |  2097m3 |
+  |  2098m8 |
+  |  2099m5 |
+  |  2100m1 |
+  | 2100m10 |
+  +---------+

Task/Five-weekends/VBA/five-weekends.vba

@@ -0,0 +1,22 @@
+Option Explicit
+
+Sub Main()
+Dim y As Long, m As Long, t As String, cpt As Long, cptm As Long
+    For y = 1900 To 2100
+        t = vbNullString
+        For m = 1 To 12 Step 2
+            If m = 9 Then m = 8
+            If Weekday(DateSerial(y, m, 1)) = vbFriday Then
+                t = t & ", " & m
+                cptm = cptm + 1
+            End If
+        Next
+        If t <> "" Then
+            Debug.Print y & t
+        Else
+            cpt = cpt + 1
+        End If
+    Next
+    Debug.Print "There is " & cptm & " months with five full weekends from the year 1900 through 2100"
+    Debug.Print "There is " & cpt & " years which don't have months with five weekends"
+End Sub