019f8fd211
git-subtree-dir: users/wpcarro git-subtree-mainline:464bbcb15cgit-subtree-split:24f5a642afChange-Id: I6105b3762b79126b3488359c95978cadb3efa789
67 lines
1.8 KiB
Python
67 lines
1.8 KiB
Python
# Write a function that accepts an array of integers and returns the indices for
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# the starting and ending integers that, if their elements were sorted, the
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# entire array would be sorted.
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################################################################################
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# First Attempt
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################################################################################
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def unsorted_substring(xs):
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ys = xs[:]; ys.sort()
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m = 0
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while xs[m] == ys[m]:
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m += 1
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if m >= len(xs):
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return -1, -1
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n = len(xs) - 1
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while xs[n] == ys[n]:
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n -= 1
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return m, n
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################################################################################
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# Second Attempt
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################################################################################
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def unsorted_substring_2(xs):
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beg = 1
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while xs[beg - 1] <= xs[beg]:
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beg += 1
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if beg >= len(xs):
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return -1, -1
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end = len(xs) - 2
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while xs[end + 1] >= xs[end]:
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end -= 1
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min_mid = xs[beg]
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max_mid = xs[beg]
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i = beg + 1
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while i <= end:
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min_mid = min(min_mid, xs[i])
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max_mid = max(max_mid, xs[i])
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i += 1
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# beg -= 1 until max(lhs) <= min(mid)
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while beg - 1 >= 0 and xs[beg - 1] >= min_mid:
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beg -= 1
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# end += 1 while max(mid) <= min(rhs)
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while end + 1 < len(xs) and max_mid >= xs[end + 1]:
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end += 1
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return beg, end
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################################################################################
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# Tests
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################################################################################
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xs = [
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[1,2,4,7,10,11,7,12,6,7,16,18,19],
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[1,2,3,4],
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[4,3,2,1],
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[1,3,2,4],
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[2,1,3,4],
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]
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for x in xs:
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print("Testing: {}".format(x))
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print("1) {}".format(unsorted_substring(x)))
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print("2) {}".format(unsorted_substring_2(x)))
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