32 lines
815 B
Ruby
32 lines
815 B
Ruby
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# A sorted array is rotated at some unknown point, Search given element in it
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# Time-complexity: O(logn),Auxiliary-space:O(1)
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# Algorithm: Binary-Search
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def search(a,key)
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lo=0
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hi=a.length-1
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while lo<=hi
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mid=lo+(hi-lo)/2
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if a[mid]==key
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return mid
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elsif a[mid]>=a[lo]
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if (a[mid]>key && a[lo]<=key)
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hi=mid-1
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else
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lo=mid+1
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end
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else
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if (a[mid]<key && a[hi]>=key)
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lo=mid+1
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else
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hi=mid-1
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end
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end
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end
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return -1
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end
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# It doesn’t look possible to search in O(Logn) time in all cases when duplicates are allowed.
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# Consider searching 0 in {2, 2, 2, 2, 2, 2, 2, 2, 0, 2} and {2, 0, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2}.
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