Classic Backtracking Problems (N-Queens, Sudoku Solver, Permutations)

Classic Backtracking Problems (N-Queens, Sudoku, Permutations)

• N-Queens: place queens row by row while tracking columns/diagonals
• Sudoku: fill digits by checking row/column/box constraints
• Permutations: build permutations by marking used elements

Focus on constraints, branching factor, and pruning for performance.