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27 lines
677 B
Ruby
27 lines
677 B
Ruby
#Given an array replace every element by product of previous and next
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#first element is replaced by product of first and second and last element by product of last and second last
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#Time-complexity: O(n),Auxiliary-space: O(1)
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def modify(a)
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len=a.length
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if len<=0
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return -1
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end
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#update first element
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prev=a[0]
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a[0]*=a[1]
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for i in 1...len-1
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current=a[i] #Keep track of current element
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a[i]=prev*a[i+1]
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prev=current #Store current element for next iteration
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end
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#update last element
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a[len-1]*=prev
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return a
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end
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modify([3,6,1,7,8,2]) # => [18, 3, 42, 8, 14, 16]
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