NQueens game - JAVA

//Backtracking

//Andrew Guandique
//Objective: Solve N-Queens puzzle game in a few unique and reversible solutions

public class NQueens {

  private static int[] b = new int[8];

  private static int s = 0;

  static boolean unsafe(int y) {

    int x = b[y]; //x = 8

    for (int i = 1; i <= y; i++) { //i < 8 i++

      int t = b[y - i]; //t = 7

      if (t == x || //if t = x || t += || t -= x

          t == x - i ||

          t == x + i) {

        return true;

      }

    }

    return false;

  }

  public static void putboard() {

    System.out.println("\n\nSolution: " + (++s));

    for (int y = 0; y < 8; y++) {

      for (int x = 0; x < 8; x++) {

        System.out.print((b[y] == x) ? "|Q" : "|_");

      }

      System.out.println("|");

    }

  }

  public static void main(String[] args) {

    int y = 0;

    b[0] = -1;

    while (y >= 0) {

      do {

        b[y]++;

      } while ((b[y] < 8) && unsafe(y));

      if (b[y] < 8) {

        if (y < 7) {

          b[++y] = -1;

        } else {

          putboard();

        }

      } else {

        y--;

      }

    }

  }

}