방문 길이

package programmers;

import java.util.HashSet;
import java.util.Objects;
import java.util.Set;

public class 방문길이 {

   private static char[] dir = new char[] {'U', 'D', 'R', 'L'};
   private static int[] dy = new int[] {-1, 1, 0, 0};
   private static int[] dx = new int[] {0, 0, 1, -1};
   private static Set<Point> set;

   public static int solution(String dirs) {
      set = new HashSet<>();

      Point lastPoint = init(dirs.charAt(0));

      for (int i = 1; i < dirs.length(); i++) {
         char nextCommand = dirs.charAt(i);
         for (int j = 0; j < 4; j++) {
            if (nextCommand == dir[j]) {
               int ny = dy[j] + lastPoint.toY;
               int nx = dx[j] + lastPoint.toX;
               if (ny < -5 || nx < -5 || ny > 5 || nx > 5) {
                  break;
               }
               lastPoint = put(lastPoint.toY, lastPoint.toX, ny, nx);
               break;
            }
         }
      }

      return set.size();
   }

   private static Point init(char c) {
      Point lastPoint;

      if (c == 'U') {
         lastPoint = put(0, 0, -1, 0);
      } else if (c == 'D') {
         lastPoint = put(0, 0, 1, 0);
      } else if (c == 'R') {
         lastPoint = put(0, 0, 0, 1);
      } else {
         lastPoint = put(0, 0, 0, -1);
      }

      return lastPoint;
   }

   private static Point put(int fromY, int fromX, int toY, int toX) {
      Point point = new Point(fromY, fromX, toY, toX);
      set.add(point);
      return point;
   }

   private static class Point {
      int fromY, fromX;
      int toY, toX;

      public Point(int fromY, int fromX, int toY, int toX) {
         this.fromY = fromY;
         this.fromX = fromX;
         this.toY = toY;
         this.toX = toX;
      }

      @Override
      public boolean equals(Object o) {
         if (this == o)
            return true;
         if (!(o instanceof Point))
            return false;
         Point point = (Point)o;
         return (fromY == point.fromY && fromX == point.fromX && toY == point.toY && toX == point.toX)
            || (fromY == point.toY && fromX == point.toX && toY == point.fromY && toX == point.fromX);
      }

      @Override
      public int hashCode() {
         return Objects.hash(toY, toX, fromY, fromX) + Objects.hash(fromY, fromX, toY, toX);
      }

   }

   public static void main(String[] args) {
      System.out.println(solution("ULURRDLLU"));
      System.out.println(solution("LULLLLLLU"));
      System.out.println(solution("UDDUUD"));
   }

}