41 lines
863 B
Ruby
41 lines
863 B
Ruby
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#Given an array reverse it without using extra-space
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#Time-complexity: O(n), Auxiliary-space: O(1)
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# Iterative
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def reverse_array(a)
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right=a.length-1
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left=0
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while(left<right)
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#swap the elements
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temp=a[left] #Swapping can be like done like this a[left],a[right]=a[right],a[left]
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a[left]=a[right]
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a[right]=temp
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left+=1
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right-=1
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end
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print a
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end
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reverse_array([1,2,3,4,5]) # => [5,4,3,2,1]
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# Recursive
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#driver program
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def driver_program(a)
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right=a.length-1
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left=0
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reverse_array(a,left,right)
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print a
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end
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def reverse_array(a,left,right)
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return if left>=right
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#swap the elements
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temp=a[left]
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a[left]=a[right]
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a[right]=temp
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reverse_array(a,left+1,right-1)
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end
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driver_program([1,2,3,4,5]) # => [5,4,3,2,1]
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