What will be the output of this code?

“`C++
#include
#include
using namespace std;

bool isSafe(vector>& grid, int row, int col, int num) {
// Check if the number is already present in the current row or column
for (int i = 0; i < 9; ++i) { if (grid[row][i] == num || grid[i][col] == num) { return false; } } // Check if the number is already present in the current 3x3 subgrid int startRow = row - row % 3; int startCol = col - col % 3; for (int i = 0; i < 3; ++i) { for (int j = 0; j < 3; ++j) { if (grid[i + startRow][j + startCol] == num) { return false; } } } return true; } bool solveSudoku(vector>& grid) {
int row, col;
bool isFilled = true;
for (row = 0; row < 9; ++row) { for (col = 0; col < 9; ++col) { if (grid[row][col] == 0) { isFilled = false; break; } } if (!isFilled) { break; } } if (isFilled) { return true; // Grid is completely filled } 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] = 0; // Backtrack } } return false; // No solution found } void printGrid(vector>& grid) {
for (int i = 0; i < 9; ++i) { for (int j = 0; j < 9; ++j) { cout << grid[i][j] << " "; } cout << endl; } } int main() { vector> grid = {
{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(grid)) {
cout << "Solution:\n"; printGrid(grid); } else { cout << "No solution exists.\n"; } return 0; } ```