time complexity of this code?

class Queen { //number of queens private static int N; //chessboard private static int[][] board = new int[100][100]; //function to check if the cell is attacked or not private static boolean isAttack(int i,int j) { int k,l; //checking if there is a queen in row or column for(k=0;kif((board[i][k] == 1) || (board[k][j] == 1)) return true; } //checking for diagonals for(k=0;kfor(l=0;lif(((k+l) == (i+j)) || ((k-l) == (i-j))) { if(board[k][l] == 1) return true; } } } return false; } private static boolean nQueen(int n) { int i,j; //if n is 0, solution found if(n==0) return true; for(i=0;ifor(j=0;j//checking if we can place a queen here or not //queen will not be placed if the place is being attacked //or already occupied if((!isAttack(i,j)) && (board[i][j]!=1)) { board[i][j] = 1; //recursion //wether we can put the next queen with this arrangment or not if(nQueen(n-1)==true) { return true; } board[i][j] = 0; } } } return false; } public static void main(String[] args) { Scanner s = new Scanner(System.in); //taking the value of N System.out.println("Enter the value of N for NxN chessboard"); N = s.nextInt(); int i,j; //calling the function nQueen(N); //printing the matix for(i=0;ifor(j=0;j