Data commit

Task/Perfect-shuffle/FreeBASIC/perfect-shuffle.basic

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+function is_in_order( d() as uinteger ) as boolean
+    'tests if a deck is in order
+    for i as uinteger = lbound(d) to ubound(d)-1
+        if d(i) > d(i+1) then return false
+    next i
+    return true
+end function
+
+sub init_deck( d() as uinteger )
+    for i as uinteger = 1 to ubound(d)
+        d(i) = i
+    next i
+    return
+end sub
+
+sub shuffle( d() as uinteger )
+    'does a faro shuffle of the deck
+    dim as integer n = ubound(d), i
+    dim as integer b( 1 to n )
+    for i = 1 to n/2
+        b(2*i-1) = d(i)
+        b(2*i)   = d(n/2+i)
+    next i
+    for i = 1 to n
+        d(i) = b(i)
+    next i
+    return
+end sub
+
+function shufs_needed( size as integer ) as uinteger
+    dim as uinteger d(1 to size), s = 0
+    init_deck(d())
+    do
+        shuffle(d())
+        s+=1
+        if is_in_order(d()) then exit do
+    loop
+    return s
+end function
+
+dim as uinteger tests(1 to 7) = {8, 24, 52, 100, 1020, 1024, 10000}, i
+for i = 1 to 7
+    print tests(i);" cards require "; shufs_needed(tests(i)); " shuffles."
+next i