1. Problem Statement (Simple Explanation): You are given a 9×9 Sudoku board, partially filled, with: Digits '1'–'9' for filled cells. '.' for empty cells. You must: Fill the empty cells so that the final board is a valid Sudoku solution : Each digit 1–9 appears exactly once in each row . Each digit 1–9 appears exactly once in each column . Each digit 1–9 appears exactly once in each 3×3 sub-box . The input is guaranteed to have exactly one solution . You must modify the board in-place . 2. Example: Input board: [ ["5","3",".",".","7",".",".",".","."], ["6",".",".","1","9","5",".",".","."], [".","9","8",".",".",".",".","6","."], ["8",".",".","....
1. Problem Statement (Simple Explanation): You’re given a 9×9 Sudoku board (char[9][9]), partially filled. You must determine if the board is valid according to Sudoku rules for the filled cells only : Each row must contain digits 1-9 without repetition . Each column must contain digits 1-9 without repetition . Each of the nine 3×3 sub-boxes must contain digits 1-9 without repetition . Notes: Empty cells are denoted by '.' and can be ignored. A valid board might not be solvable; you only validate current filled cells. 2. Examples: Example 1 (Valid): [["5","3",".",".","7",".",".",".","."] ,["6",".",".","1","9","5",".",".","."] ,[".","9","8",".",".",".",".","6","."] ,["8",".",...