/* A recursive utility function to solve N Queen problem */
bool solveNQUtil(int board[N][N], int col)
{
/* base case: If all queens are placed then return true */
if (col >= N)
return true;
/* Consider this column and try placing this queen in all rows
one by one */
for (int i = 0; i < N; i++)
{
/* Check if queen can be placed on board[i][col] */
if ( isSafe(board, i, col) )
{
/* Place this queen in board[i][col] */
board[i][col] = 1;
/* recur to place rest of the queens */
if ( solveNQUtil(board, col + 1) == true )
return true;
/* If placing queen in board[i][col] doesn't lead to a solution
then remove queen from board[i][col] */
board[i][col] = 0; // BACKTRACK
}
}
/* If queen can not be place in any row in this colum col
then return false */
return false;
}
bool solveNQ(){
int board[N][N] = { {0, 0, 0, 0},
{0, 0, 0, 0},
{0, 0, 0, 0},
{0, 0, 0, 0}
};
if ( solveNQUtil(board, 0) == false ){
printf("Solution does not exist");
return false;
}
printSolution(board);
return true;
}
bool solveNQUtil(int board[N][N], int col){
if (col >= N) return true;
for (int i = 0; i < N; i++){
if ( isSafe(board, i, col) ){
board[i][col] = 1;
if ( solveNQUtil(board, col + 1) == true ) return true;
board[i][col] = 0;
}
}
return false;
}
bool solveNQUtil(int board[N][N], int col)
{
if (col >= N)
return true;
//check all the rows in this column
for (int i = 0; i < N; ++i)
{
if (isSafe(board, i, col))
{
board[i][col] = 1;
if (solveNQUtil(board, col + 1)) return true;
//BackTracking
board[i][col] = 0;
}
}
return false;
}