Q2: Print missing numbers
Input: [2, 4, 7, 13, 20]
Output: "0,1,3,5,6,8-12,14-19,21-99"
Given a sorted list of numbers, print all missing numbers in the range from 0 to 99. Consecutive missing values should be compressed into ranges.
The key idea is to scan the sorted array and print every number missing from the range <code>0</code> to <code>99</code>, compressing consecutive gaps into intervals. A clean solution checks the missing prefix before the first value, the gaps between adjacent values, and the suffix after the last value up to <code>99</code>. This is a classic OA-style array traversal and formatting problem with careful boundary handling.
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