Create Sudoku_Solver.cpp

Sudoku_Solver.cpp

@@ -0,0 +1,99 @@
+/*
+SUDOKU SOLVER
+// Time ->O(9^(n*n))
+*/
+
+#include <bits/stdc++.h>
+using namespace std;
+
+bool check(int mat[9][9], int no, int i, int j)
+{
+    // checking row and column
+    for (int k = 0; k < 9; k++)
+    {
+        if (mat[i][k] == no || mat[k][j] == no)
+        {
+            return false;
+        }
+    }
+    // checking 3x3 subgrid
+    int si = i - i % 3;
+    int sj = j - j % 3;
+    for (int i = si; i < si + 3; i++)
+    {
+        for (int j = sj; j < sj + 3; j++)
+        {
+            if (mat[i][j] == no)
+            {
+                return false;
+            }
+        }
+    }
+    return true;
+}
+bool solve(int matrix[9][9])
+{
+    for (int i = 0; i < 9; i++)
+    {
+        for (int j = 0; j < 9; j++)
+        {
+            if (matrix[i][j] == 0)
+            {
+                for (int no = 1; no <= 9; no++)
+                {
+                    if (check(matrix, no, i, j))
+                    {
+                        matrix[i][j] = no;
+                        if (solve(matrix) == true)
+                            return true;
+                        else
+                            matrix[i][j] = 0;
+                    }
+                }
+                return false;
+            }
+        }
+    }
+    return true;
+}
+bool isItSudoku(int matrix[9][9])
+{
+    // Write your code here.
+    if (solve(matrix) == true)
+    {
+        return true;
+    }
+    return false;
+}
+void printGrid(vector<vector<int>> &grid)
+{
+    for (int row = 0; row < grid.size(); row++)
+    {
+        for (int col = 0; col < grid.size(); col++)
+            cout << grid[row][col] << " ";
+        cout << endl;
+    }
+}
+
+int main()
+{
+
+    vector<vector<int>> grid{{3, 0, 6, 5, 0, 8, 4, 0, 0},
+                             {5, 2, 0, 0, 0, 0, 0, 0, 0},
+                             {0, 8, 7, 0, 0, 0, 0, 3, 1},
+                             {0, 0, 3, 0, 1, 0, 0, 8, 0},
+                             {9, 0, 0, 8, 6, 3, 0, 0, 5},
+                             {0, 5, 0, 0, 9, 0, 6, 0, 0},
+                             {1, 3, 0, 0, 0, 0, 2, 5, 0},
+                             {0, 0, 0, 0, 0, 0, 0, 7, 4},
+                             {0, 0, 5, 2, 0, 6, 3, 0, 0}};
+
+    // printGrid(grid);
+    if (solve(grid) == true)
+        printGrid(grid);
+    else
+        cout << "No solution exists";
+
+    return 0;
+}
+