Status: IN
O(n log n) sorting as a preprocessing step is the standard technique for reducing complex pair/ordering problems to simple linear-scan algorithms via two-pointer, adjacent-pair, or greedy strategies.
Sorting is the universal complexity bridge from quadratic brute-force to n-log-n solutions
Depends on (SL): sort-then-two-pointer-pattern, meeting-rooms-sort-then-scan, array-partition-sort-greedy, subsequence-limited-sum-greedy-sort