Singly-linked list/Reversal: Difference between revisions
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(Created page with "{{draft task}} :I don't even know how to reverse a linked-list, and I don't even know what that is. -- a YouTuber. Reverse a linked list. Obviously you can do it by turning it into a normal list and back, but feel free to use a smarter, possibly more efficient way.") |
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Reverse a linked list. Obviously you can do it by turning it into a normal list and back, but feel free to use a smarter, possibly more efficient way. |
Reverse a linked list. Obviously you can do it by turning it into a normal list and back, but feel free to use a smarter, possibly more efficient way. |
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=={{header|ALGOL 68}}== |
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Using the code from the [[Singly-linked list/Traversal#ALGOL_68]] Task |
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<syntaxhighlight lang="algol68"> |
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BEGIN |
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MODE STRINGLIST = STRUCT(STRING value, REF STRINGLIST next); |
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# construct a STRINGLIST wuth a few elments # |
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STRINGLIST list := ("Big", |
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LOC STRINGLIST := ("fjords", |
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LOC STRINGLIST := ("vex", |
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LOC STRINGLIST := ("quick", |
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LOC STRINGLIST := ("waltz", |
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LOC STRINGLIST := ("nymph",NIL)))))); |
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# print the list and buuild the reverse list # |
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REF STRINGLIST node := list; |
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REF STRINGLIST reverse := REF STRINGLIST(NIL); |
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WHILE node ISNT REF STRINGLIST(NIL) DO |
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reverse := HEAP STRINGLIST |
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:= STRINGLIST( value OF node, reverse ); |
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print((value OF node, space)); |
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node := next OF node |
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OD; |
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print(newline); |
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# print the reverse list # |
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node := reverse; |
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WHILE node ISNT REF STRINGLIST(NIL) DO |
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print((value OF node, space)); |
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node := next OF node |
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OD; |
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print(newline) |
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END |
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</syntaxhighlight> |
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{{out}} |
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<pre> |
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Big fjords vex quick waltz nymph |
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nymph waltz quick vex fjords Big |
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</pre> |
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