81 lines
2.1 KiB
C#
81 lines
2.1 KiB
C#
namespace _36._Valid_Sudoku;
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public class Solution
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{
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public bool IsValidSudoku(char[][] board)
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{
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return CheckRows(board) && CheckColumns(board) && CheckSubBoxes(board);
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}
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private bool CheckRows(char[][] board)
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{
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foreach (char[] row in board)
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{
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HashSet<char> rowSet = new HashSet<char>();
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foreach (char c in row)
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{
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if (c != '.')
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{
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int prevCount = rowSet.Count;
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rowSet.Add(c);
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if (prevCount == rowSet.Count)
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return false;
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}
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}
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}
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return true;
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}
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private bool CheckColumns(char[][] board)
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{
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for (int columnIndex = 0; columnIndex < board[0].Length; columnIndex++)
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{
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HashSet<char> column = new HashSet<char>();
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for (int rowIndex = 0; rowIndex < board[columnIndex].Length; rowIndex++)
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{
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char ch = board[rowIndex][columnIndex];
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if (ch != '.')
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{
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int prevCount = column.Count;
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column.Add(ch);
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if (prevCount == column.Count)
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return false;
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}
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}
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}
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return true;
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}
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private bool CheckSubBoxes(char[][] board)
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{
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for (int i = 0; i < 27; i += 3)
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{
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int y = i / 9 * 3;
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int x = i % 9;
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if (CheckSubBox(board, y, x) == false)
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return false;
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}
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return true;
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}
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private bool CheckSubBox(char[][] board, int startY, int startX)
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{
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HashSet<char> set = new HashSet<char>();
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for (int y = startY; y < startY + 3; y++)
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{
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for (int x = startX; x < startX + 3; x++)
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{
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char ch = board[y][x];
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if (ch != '.')
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{
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int prev = set.Count;
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set.Add(ch);
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if (prev == set.Count)
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return false;
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}
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}
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}
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return true;
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}
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}
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