commit

Author: AdityaSolanki189

Projects/RachitCode.exe

@@ -0,0 +1,107 @@
+#include <iostream>
+#include <cstdio>
+#include <cstring>
+#include <cstdlib>
+using namespace std;
+#define UNASSIGNED 0
+#define N 9
+
+bool FindUnassignedLocation(int grid[N][N], int &row, int &col);
+bool isSafe(int grid[N][N], int row, int col, int num);
+
+/* assign values to all unassigned locations for Sudoku solution  
+ */
+bool SolveSudoku(int grid[N][N])
+{
+    int row, col;
+    if (!FindUnassignedLocation(grid, row, col))
+       return true;
+    for (int num = 1; num <= 9; num++)
+    {
+    if (isSafe(grid, row, col, num))
+    {
+        grid[row][col] = num;
+        if (SolveSudoku(grid))
+            return true;
+        grid[row][col] = UNASSIGNED;
+    }
+    }
+    return false;
+}
+
+/* Searches the grid to find an entry that is still unassigned. */
+bool FindUnassignedLocation(int grid[N][N], int &row, int &col)
+{
+    for (row = 0; row < N; row++)
+        for (col = 0; col < N; col++)
+            if (grid[row][col] == UNASSIGNED)
+                return true;
+    return false;
+}
+
+/* Returns whether any assigned entry n the specified row matches 
+   the given number. */
+bool UsedInRow(int grid[N][N], int row, int num)
+{
+    for (int col = 0; col < N; col++)
+    if (grid[row][col] == num)
+        return true;
+    return false;
+}
+
+/* Returns whether any assigned entry in the specified column matches 
+   the given number. */
+bool UsedInCol(int grid[N][N], int col, int num)
+{
+    for (int row = 0; row < N; row++)
+        if (grid[row][col] == num)
+            return true;
+    return false;
+}
+
+/* Returns whether any assigned entry within the specified 3x3 box matches 
+   the given number. */
+bool UsedInBox(int grid[N][N], int boxStartRow, int boxStartCol, int num)
+{
+    for (int row = 0; row < 3; row++)
+        for (int col = 0; col < 3; col++)
+            if (grid[row+boxStartRow][col+boxStartCol] == num)
+                return true;
+    return false;
+}
+
+/* Returns whether it will be legal to assign num to the given row,col location. 
+ */
+bool isSafe(int grid[N][N], int row, int col, int num)
+{
+    return !UsedInRow(grid, row, num) && !UsedInCol(grid, col, num) &&
+       !UsedInBox(grid, row - row % 3 , col - col % 3, num);
+}
+
+void printGrid(int grid[N][N])
+{
+    for (int row = 0; row < N; row++)
+    {
+        for (int col = 0; col < N; col++)
+            cout<<grid[row][col]<<"  ";
+        cout<<endl;
+    }
+}
+
+int main()
+{
+    int grid[N][N] = {{0, 0, 0, 0, 0, 0, 0, 0, 0},
+                      {0, 0, 0, 9, 3, 7, 2, 0, 0},
+                      {0, 0, 0, 2, 4, 8, 9, 7, 0},
+                      {4, 0, 3, 0, 0, 0, 5, 6, 0},
+                      {0, 6, 0, 0, 0, 0, 7, 9, 0},
+                      {0, 5, 0, 7, 0, 0, 3, 2, 0},
+                      {0, 9, 0, 0, 0, 1, 0, 0, 0},
+                      {0, 0, 6, 8, 2, 0, 0, 0, 0},
+                      {1, 0, 0, 0, 0, 4, 0, 0, 0}};
+    if (SolveSudoku(grid) == true)
+        printGrid(grid);
+    else
+        cout<<"No solution exists"<<endl;
+    return 0;
+}