Sudoku Solver

Write a program to solve a Sudoku puzzle by filling the empty cells.

Empty cells are indicated by the character '.'.

You may assume that there will be only one unique solution.

A sudoku puzzle...

...and its solution numbers marked in red.

bool isValid(vector> & board, int x, int y){
        for(int i=0; i>& board) {
        for(int i=0; i>& board) {
        solveSudo(board);
    }