from typing import List, Tuple, Optional

def solve_backtracking(n: int, find_all: bool = False) -> List[List[int]]:
    """
    Backtracking algorithm for N-Queens.
    Returns a list of solutions. Each solution is a list of column indices for each row.
    """
    solutions = []
    board = [-1] * n  # board[row] = col
    cols = [False] * n
    diag1 = [False] * (2 * n - 1) # row + col
    diag2 = [False] * (2 * n - 1) # row - col + (n - 1)

    def backtrack(row: int):
        if row == n:
            solutions.append(board[:])
            return True

        for col in range(n):
            if not cols[col] and not diag1[row + col] and not diag2[row - col + n - 1]:
                board[row] = col
                cols[col] = True
                diag1[row + col] = True
                diag2[row - col + n - 1] = True

                if backtrack(row + 1):
                    if not find_all:
                        return True
                
                # Backtrack
                cols[col] = False
                diag1[row + col] = False
                diag2[row - col + n - 1] = False
        
        return False

    backtrack(0)
    return solutions