オフラインリアルタイムどう書く第6回の参考問題（Java解答） ref: http://qiita.com/items/e61a4181d1e033ef2b4d

Lintersection.java

package sample6;

import static org.junit.Assert.assertEquals;

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

import org.junit.Test;

/**
 * 問題: http://nabetani.sakura.ne.jp/hena/ord6lintersection/
 */
public class Lintersection {

    public String solve(String input) {
        String[] split = input.split(",");
        String[] first = split[0].split("-");
        String[] second = split[1].split("-");

        Set<String> firstL = getL(first);
        Set<String> secondL = getL(second);

        int counter = 0;
        for (String string : secondL) {
            boolean canAdd = firstL.add(string);
            if (canAdd == false) {
                counter++;
            }
        }
        return String.valueOf(counter);
    }

    protected Set<String> getL(String[] points) {

        int x0 = Integer.valueOf(String.valueOf(points[0].charAt(0)));
        int y0 = Integer.valueOf(String.valueOf(points[0].charAt(1)));
        int x1 = Integer.valueOf(String.valueOf(points[1].charAt(0)));
        int y1 = Integer.valueOf(String.valueOf(points[1].charAt(1)));

        Set<String> tmp = new HashSet<>();
        Set<String> firstBlock = makeBlock(x0, y0, x1, y1, tmp);

        int x2 = Integer.valueOf(String.valueOf(points[2].charAt(0)));
        int y2 = Integer.valueOf(String.valueOf(points[2].charAt(1)));

        Set<String> result = makeBlock(x2, y2, x0, y0, firstBlock);
        return result;
    }

    protected Set<String> makeBlock(int x0, int y0, int x1, int y1,
            Set<String> set) {
        Set<String> result = new HashSet<>(set);
        int maxX = x0 < x1 ? x1 : x0;
        int minX = x0 < x1 ? x0 : x1;
        int maxY = y0 < y1 ? y1 : y0;
        int minY = y0 < y1 ? y0 : y1;

        for (int i = minX; i < maxX + 1; i++) {
            for (int k = minY; k < maxY + 1; k++) {
                result.add(String.valueOf(i) + String.valueOf(k));
            }
        }

        return result;
    }

    public static void main(String[] args) {
        Lintersection li = new Lintersection();
        System.out.println(li.solve("23-94-28,89-06-51"));
    }

    @Test
    public void testSolve() throws Exception {

        test("23-94-28,89-06-51", 11);
        test("11-84-58,02-73-69", 40);
        test("18-41-86,77-04-32", 26);
        test("81-88-23,64-58-14", 0);
        test("31-29-07,41-87-69", 0);
        test("83-13-40,18-10-94", 1);
        test("77-80-92,21-72-38", 2);
        test("57-70-91,55-19-08", 3);
        test("18-22-75,66-80-91", 4);
        test("51-93-78,54-49-06", 5);
        test("58-70-96,17-43-76", 6);
        test("58-07-12,58-82-93", 7);
        test("41-29-07,35-95-88", 8);
        test("88-26-60,42-29-07", 9);
        test("18-40-85,34-40-91", 10);
        test("36-60-96,53-96-89", 11);
        test("51-39-02,44-98-69", 12);
        test("48-06-20,76-04-42", 13);
        test("85-29-18,26-50-93", 14);
        test("27-50-91,43-29-07", 15);
        test("57-06-20,48-60-91", 16);
        test("52-98-89,21-76-67", 17);
        test("67-12-40,45-80-92", 18);
        test("47-03-10,26-30-82", 19);
        test("74-28-06,21-86-37", 20);
        test("65-01-20,73-39-05", 21);
        test("17-72-86,36-50-94", 22);
        test("51-29-07,77-15-41", 23);
        test("33-98-39,82-16-02", 24);
        test("75-05-10,37-81-96", 25);
        test("72-58-06,48-80-96", 26);
        test("81-67-16,21-91-59", 27);
        test("13-96-57,24-96-79", 28);
        test("57-04-32,51-18-06", 29);
        test("88-03-52,28-41-86", 30);
        test("78-04-61,13-86-49", 31);
        test("58-12-20,27-50-85", 32);
        test("61-19-05,71-68-15", 33);
        test("63-29-16,18-31-83", 34);
        test("16-50-91,32-98-79", 35);
        test("82-17-03,38-40-81", 36);
        test("72-48-04,11-98-39", 37);
        test("77-05-10,28-50-62", 38);
        test("38-50-91,11-86-57", 39);
        test("87-05-10,13-97-69", 40);
        test("11-86-49,22-98-89", 44);
        test("11-97-69,12-86-67", 46);
        test("11-95-69,71-49-05", 47);
        test("28-31-92,13-98-79", 48);
    }

    protected void test(String string, int i) {
        Lintersection li = new Lintersection();
        assertEquals(String.valueOf(i), li.solve(string));
    }
}