CoursesBacktracking & GreedyConstraint Search
Boss: N-Queens
The island's final test: place n queens so none attack. Row-by-row construction plus three O(1) sets — columns, row − col, row + col — replace board rescans with three lookups; the trap is checking columns only.
AlgoFox Pro
Backtracking & Greedy is part of AlgoFox Pro
You can read the whole course outline here. The exercises are in the app, along with your streak, your mistake review, and the progress that carries across your devices.
Pro starts with a 3 day free trial. The app store decides who is eligible for an introductory offer, and a lapsed subscription does not get another one.
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