 Solution

ID: past-exam-of-the-year-1-of-the-computer-science-course-of-the-university-of-oxford/2014/functional-programming-design-and-analysis-of-algorithms/6/a/solution

Describe routes by array indices, so repeated entry values cannot confuse positions. Two valid routes are

0 \to 2 \to 4 \to 9 \to 10, 0 \to 2 \to 3 \to 4 \to 8 \to 10.

2, 2, 5, 1

, bounded respectively by

A [0] = 2

A [2] = 3

A [4] = 5

A [9] = 7

2, 1, 1, 4, 2

, bounded by

2, 3, 3, 5, 2

at its departing positions. Both reach the final index without landing at the zero entry at index six.

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