33 lines
788 B
Ruby
33 lines
788 B
Ruby
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#Given an array A[] consisting 0s, 1s and 2s, put all 0s first, then all 1s and all 2s in last.
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##Brute-force: Count 0s and 1s (using 2 varibales)and rewrite array first with counted zeros then by counted 1s and then by 2s
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#Time-complexity:O(n),Auxiliary-space:O(1)
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##Algorithm: Dutch National Flag Algorithm
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#Time-complexity:O(n),Auxiliary-space:O(1)
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def segregate(a)
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right=a.length-1
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left=0
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current=0
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while(current<=right)
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if a[current]==0
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swap(a,left,current)
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left+=1
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current+=1
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elsif a[current]==2
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swap(a,right,current)
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right-=1
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else
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current+=1
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end
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end
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print a
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end
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def swap(a,i,j)
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a[i],a[j]=a[j],a[i]
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end
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segregate([0, 1, 1, 0, 1, 2, 1, 2, 0, 0, 0, 1])
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