Sorting Based — Greedy Patterns
The Sorting Based pattern applies when you need the Sorting Based technique within the Greedy Patterns pattern. Its time complexity is O(n log n) and space complexity O(1) to O(n), depending on the sort implementation. It is used in 4 problems on Thita, including Assign Cookies, Candy and Queue Reconstruction by Height. Common variations are Buy/Sell Stock and Jump Game Reachability/Minimization.
Solve greedy problems that require sorting as preprocessing step for optimal solutions.
Sorting Based is one of the 7 subpatterns of the Greedy Patterns pattern, which covers interval scheduling, jump games, stock trading, and task scheduling. The whole pattern is about 3 hours of study. This subpattern is an important variation worth recognising on sight.
What Sorting Based covers
Master greedy algorithms including interval scheduling, jump games, stock trading, and task scheduling. Make locally optimal choices for global optimization. Problems in this subpattern are usually searched for as greedy sorting, sort first, sorted greedy, queue reconstruction.
How to practise Sorting Based on Thita.ai
Read the theory for Sorting Based, then work the problems attached to it in the browser editor. Your solution runs against the problem's test cases, and the AI coach offers a hint about the technique you are missing rather than a finished solution. Progress is tracked per subpattern, so the Greedy Patterns tracker shows this one as covered once you have solved its problems.
Other subpatterns in Greedy Patterns
- Jump Game Reachability/Minimization — Solve jump game problems using greedy approach. Check reachability and find minimum jumps.
- Interval Merging/Scheduling — Master interval problems including merge intervals, insert interval, and non-overlapping intervals.
- Buy/Sell Stock — Optimize stock trading with greedy strategy. Single transaction and multiple transactions.
- Task Scheduling (Frequency Based) — Schedule tasks with cooldown using frequency-based greedy approach.
- Line Sweep — Master the line sweep technique for interval and geometric problems. Process events in sorted order for overlap counting, skyline, and meeting room problems.
- Gas Station Circuit — Find the starting gas station index to complete a circular route using greedy approach.
Related DSA patterns
- Tree Traversal Patterns (DFS & BFS) — Preorder, inorder, level order traversal, LCA, and serialization.
- Heap (Priority Queue) Patterns — Top K elements, K-way merge, two heaps for median, and scheduling.
- Backtracking Patterns — Subsets, permutations, combinations, N-Queens, and word search.
- Dynamic Programming (DP) Patterns — Fibonacci, Kadane, knapsack, LCS, LIS, edit distance, grid paths, and word break.
Where to go next
Sorting Based is one lesson in a 16-pattern DSA course. If you are preparing end to end, work the interview-critical patterns first and use the pattern sheet as the checklist; if you are here for one technique, the Greedy Patterns guide is the shortest path back to the rest of it.