completed

sudoku.go

@@ -1 +1,142 @@
 package main
+
+import (
+	"fmt"
+)
+
+func isValid(board [][]int, row, col, num int) bool {
+	// Check the line
+	for i := 0; i < 9; i++ {
+		if board[row][i] == num {
+			return false
+		}
+	}
+
+	// Check the column
+	for i := 0; i < 9; i++ {
+		if board[i][col] == num {
+			return false
+		}
+	}
+
+	// Check the box
+	startRow, startCol := row-row%3, col-col%3
+	for i := 0; i < 3; i++ {
+		for j := 0; j < 3; j++ {
+			if board[i+startRow][j+startCol] == num {
+				return false
+			}
+		}
+	}
+
+	return true
+}
+
+func solved(board [][]int) bool {
+	// Check if each row, column, and 3x3 subgrid contains numbers from 1 to 9 without repetition
+	return checkRows(board) && checkCols(board) && checkSubgrids(board)
+}
+
+func checkRows(board [][]int) bool {
+	for i := 0; i < 9; i++ {
+		seen := make(map[int]bool)
+		for j := 0; j < 9; j++ {
+			num := board[i][j]
+			if num != 0 && seen[num] {
+				return false // Duplicate in row
+			}
+			seen[num] = true
+		}
+	}
+	return true
+}
+
+func checkCols(board [][]int) bool {
+	for j := 0; j < 9; j++ {
+		seen := make(map[int]bool)
+		for i := 0; i < 9; i++ {
+			num := board[i][j]
+			if num != 0 && seen[num] {
+				return false // Duplicate in column
+			}
+			seen[num] = true
+		}
+	}
+	return true
+}
+
+func checkSubgrids(board [][]int) bool {
+	for startRow := 0; startRow < 9; startRow += 3 {
+		for startCol := 0; startCol < 9; startCol += 3 {
+			if !checkSubgrid(board, startRow, startCol) {
+				return false
+			}
+		}
+	}
+	return true
+}
+
+func checkSubgrid(board [][]int, startRow, startCol int) bool {
+	seen := make(map[int]bool)
+	for i := 0; i < 3; i++ {
+		for j := 0; j < 3; j++ {
+			num := board[i+startRow][j+startCol]
+			if num != 0 && seen[num] {
+				return false // Duplicate in subgrid
+			}
+			seen[num] = true
+		}
+	}
+	return true
+}
+
+func deepCopy(board [][]int) [][]int {
+	copyBoard := make([][]int, len(board))
+	for i := range board {
+		copyBoard[i] = make([]int, len(board[i]))
+		copy(copyBoard[i], board[i])
+	}
+	return copyBoard
+}
+
+func SolveSudoku(board [][]int) [][]int {
+	fmt.Println("Entering SolveSudoku")
+	for i := 0; i < 9; i++ {
+		for j := 0; j < 9; j++ {
+			if board[i][j] == 0 {
+				for num := 1; num <= 9; num++ {
+					if isValid(board, i, j, num) {
+						boardCopy := deepCopy(board) // Create a copy of the board
+						boardCopy[i][j] = num
+
+						fmt.Printf("Trying %d at (%d, %d)\n", num, i, j)
+						fmt.Println("Current board:")
+						printBoard(boardCopy)
+
+						if solved(boardCopy) {
+							fmt.Println("Board solved:")
+							printBoard(boardCopy)
+							return boardCopy
+						} else {
+							fmt.Println("Recursive call...")
+							result := SolveSudoku(boardCopy)
+							fmt.Println("Back from recursive call")
+							printBoard(result)
+						}
+					}
+				}
+				fmt.Printf("No valid number found at (%d, %d)\n", i, j)
+				return board // Return the original board if no valid number is found
+			}
+		}
+	}
+	fmt.Println("Exiting SolveSudoku")
+	return board
+}
+
+func printBoard(board [][]int) {
+	for _, row := range board {
+		fmt.Println(row)
+	}
+	fmt.Println()
+}