Backtracking builds solutions incrementally, abandoning a path as soon as it cannot lead to a valid solution.
The core idea: Try a choice. If it leads to a dead end, undo it (backtrack) and try another choice. This explores the entire solution space systematically without explicitly generating all possibilities.
I'll teach you the backtracking template, pruning strategies, and classic problems: permutations, combinations, subsets, N-Queens, and Sudoku.