Merge pull request #48 from akshit397a/patch-8

Create Suduko_Solver.cpp

games-based-on-dsa/Suduko_Solver.cpp

@@ -0,0 +1,82 @@
+// Suduko Solver
+#include <iostream>
+#include <vector>
+
+#define N 9
+
+// Function to print the Sudoku board
+void printBoard(const std::vector<std::vector<int>>& board) {
+    for (const auto& row : board) {
+        for (int num : row) {
+            std::cout << num << " ";
+        }
+        std::cout << std::endl;
+    }
+}
+
+// Function to check if placing num in board[row][col] is valid
+bool isSafe(const std::vector<std::vector<int>>& board, int row, int col, int num) {
+    // Check the row and column
+    for (int x = 0; x < N; x++) {
+        if (board[row][x] == num || board[x][col] == num) {
+            return false;
+        }
+    }
+    // Check the 3x3 sub-grid
+    int startRow = row - row % 3, startCol = col - col % 3;
+    for (int i = 0; i < 3; i++) {
+        for (int j = 0; j < 3; j++) {
+            if (board[i + startRow][j + startCol] == num) {
+                return false;
+            }
+        }
+    }
+    return true;
+}
+
+// Backtracking function to solve Sudoku
+bool solveSudoku(std::vector<std::vector<int>>& board) {
+    for (int row = 0; row < N; row++) {
+        for (int col = 0; col < N; col++) {
+            // Find an empty cell
+            if (board[row][col] == 0) {
+                // Try numbers from 1 to 9
+                for (int num = 1; num <= N; num++) {
+                    if (isSafe(board, row, col, num)) {
+                        board[row][col] = num; // Place the number
+                        // Recursively try to solve the rest of the board
+                        if (solveSudoku(board)) {
+                            return true;
+                        }
+                        // If it didn't work out, reset and try again
+                        board[row][col] = 0;
+                    }
+                }
+                return false; // No number can be placed, backtrack
+            }
+        }
+    }
+    return true; // Solved!
+}
+
+int main() {
+    // Example Sudoku puzzle (0 represents empty cells)
+    std::vector<std::vector<int>> board = {
+        {5, 3, 0, 0, 7, 0, 0, 0, 0},
+        {6, 0, 0, 1, 9, 5, 0, 0, 0},
+        {0, 9, 8, 0, 0, 0, 0, 6, 0},
+        {8, 0, 0, 0, 6, 0, 0, 0, 3},
+        {4, 0, 0, 8, 0, 3, 0, 0, 1},
+        {7, 0, 0, 0, 2, 0, 0, 0, 6},
+        {0, 6, 0, 0, 0, 0, 2, 8, 0},
+        {0, 0, 0, 4, 1, 9, 0, 0, 5},
+        {0, 0, 0, 0, 8, 0, 0 ,7 ,9}
+    };
+    if (solveSudoku(board)) {
+        std::cout << "Solved Sudoku:\n";
+        printBoard(board);
+    } else {
+        std::cout << "No solution exists.\n";
+    }
+    return 0;
+}