Implemented sudoku.go

sudoku.go

@@ -1 +1,50 @@
 package main
+
+
+// SolveSudoku SolveSudoku Problem
+func SolveSudoku(board [][]int) [][]int {
+	solve(board)
+	return board
+}
+
+
+// Solve uses a recursive approach to attempt solving the Sudoku puzzle.
+// The parameter 'board' represents the Sudoku board, which is a 9x9 2D array.
+// The function tries to fill each empty cell to satisfy Sudoku rules.
+// It returns true if a solution is found, and false otherwise.
+func solve(board [][]int) bool {
+	for i := 0; i < 9; i++ {
+		for j := 0; j < 9; j++ {// If the current cell is empty
+			if board[i][j] == 0 {// Try filling numbers 1 to 9
+				for num := 1; num <= 9; num++ {// Check if the current number is valid at the current position
+					if isValid(board, i, j, num) {// If valid, place the number in the current position
+						board[i][j] = num// Recursively call solve to continue filling the next empty cell
+						if solve(board) {// If a solution is found, return true
+							return true
+						}// If recursion fails to find a solution, reset the current position to 0 and backtrack
+						board[i][j] = 0
+					}
+				}// If all numbers have been tried and none is valid, return false indicating no solution
+				return false
+			}
+		}
+	}// All cells are filled, indicating a solution is found, return true
+	return true
+}
+
+// isValid checks if the given position is valid, if the current number can be placed without violating Sudoku rules.
+// The parameters 'board' represents the Sudoku board, 'row' and 'col' indicate the position to check, and 'num' is the number to be placed.
+// It returns true if the current position allows placing the number, and false if there is a violation.
+func isValid(board [][]int, row, col, num int) bool {
+	for i := 0; i < 9; i++ {// Check if the current number is repeated in the current row or column
+		if board[row][i] == num || board[i][col] == num {
+			return false
+		}
+		// check neighborhood (3*3)
+		if board[3*(row/3)+i/3][3*(col/3)+i%3] == num {
+			return false
+		}
+	}
+	return true
+}
+