HackerRank - Algorithm / Implementation / Queen's Attack

Solution.java

import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;

public class Solution {

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        int k = in.nextInt();
        int rQueen = in.nextInt()-1;
        int cQueen = in.nextInt()-1;
        /*
        d0 | r0 | d1
        ------------
        r1 | R  | r2
        ------------
        d2 | r3 | d3
        
        d0 -> (d0.c+d0.r = R.c+R.r) <r
        r0 -> =c <r
        d1 -> (d1.c-d1.r = R.c-R.r) <r
        r1 -> =r <c
        r2 -> =r >c
        d2 -> (d1.c-d1.r = R.c-R.r) >r
        r3 -> =c >r
        d3 -> (d0.c+d0.r = R.c+R.r) >r
        
        */

        int d0,d1,d2,d3,r0,r1,r2,r3;
        d0 = r0 = d1 = r1 = Integer.MIN_VALUE;
        r2 = d2 = r3 = d3 = Integer.MAX_VALUE;

        for(int a0 = 0; a0 < k; a0++){
            int rObstacle = in.nextInt()-1;
            int cObstacle = in.nextInt()-1;
            if(cObstacle == cQueen){
                if(rObstacle < rQueen && rObstacle > r0)
                    r0 = rObstacle;
                else if(rObstacle > rQueen && rObstacle < r3)
                    r3 = rObstacle;
            }else if(rObstacle == rQueen){
                if(cObstacle < cQueen && cObstacle > r1)
                    r1 = cObstacle;
                else if(cObstacle > cQueen && cObstacle < r2)
                    r2 = cObstacle;
            }else if((cObstacle - rObstacle) == (cQueen - rQueen)){
                if(rObstacle < rQueen && rObstacle > d0)
                    d0 = rObstacle;
                else if(rObstacle > rQueen && rObstacle < d3)
                    d3 = rObstacle;
            }else if((cObstacle + rObstacle) == (cQueen + rQueen)){
                if(rObstacle < rQueen && rObstacle > d1)
                    d1 = rObstacle;
                else if(rObstacle > rQueen && rObstacle < d2)
                    d2 = rObstacle;
            }
        }

        int total = 0;
        /*
                 0  1  2  3
                ___________
            0   |x  o  o  x
                ------------
            1   |0  x  o  x
                ------------
            2   |0  0  x  x
                -------------
            3   |x  x  x  R
        */
        total += Math.min((rQueen - Math.max(0,d0+1)),cQueen);
        total += (rQueen - Math.max(0,r0+1));
        total += Math.min((rQueen - Math.max(0,d1+1)),(n - 1 - cQueen));
        total += (cQueen - Math.max(0,r1+1));
        total += (Math.min(r2-1,n-1) - cQueen);
        total += Math.min((Math.min(d2-1,n-1) - rQueen),cQueen);
        total += (Math.min(r3-1,n-1) - rQueen);
        total += Math.min((Math.min(d3-1,n-1) - rQueen),(n - 1 - cQueen));
                
        System.out.println(total);

    }
}