201912-2 回收站选址

输入输出样例

样例1

输入

7
1 2
2 1
0 0
1 1
1 0
2 0
0 1

输出

0
0
1
0
0

样例2

输入

2
0 0
-100000 10

输出

0
0
0
0
0

样例3

输入

11
9 10
10 10
11 10
12 10
13 10
11 9
11 8
12 9
10 9
10 11
12 11

输出

0
2
1
0
0

题解一

遍历每一个的点，考察其是否符合回收站的要求，再计算其得分。总点数n的数据范围不大，但是坐标的范围比较大，因此不能用数组存储，用集合来存储。
100分。

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.*;
public class Main {
    public static void main(String[] args) throws IOException {
        final int[] DISX_1 = new int[] { 0, 0, -1, 1 };
        final int[] DISY_1 = new int[] { -1, 1, 0, 0 };
        final int[] DISX_2 = new int[] { -1, 1, -1, 1 };
        final int[] DISY_2 = new int[] { -1, -1, 1, 1 };
        final int DIR_NUM = 4;
        BufferedReader scanner = new BufferedReader(new InputStreamReader(System.in));
        int n = Integer.parseInt(scanner.readLine());
        Set<Point> set = new HashSet<>();
        String[] strs;
        for (int i = 0; i < n; ++i) {
            strs = scanner.readLine().trim().split(" ");
            set.add(new Point(Integer.parseInt(strs[0]), Integer.parseInt(strs[1])));
        }
        int[] ans = new int[5];
        Point temp = new Point();
        int junk;
        int score;
        for (Point p : set) {
            junk = 0;
            for (int i = 0; i < DIR_NUM; ++i) {
                temp.x = p.x + DISX_1[i];
                temp.y = p.y + DISY_1[i];
                if (set.contains(temp)) {
                    ++junk;
                } else {
                    break;
                }
            }
            if (junk == 4) {
                score = 0;
                for (int i = 0; i < DIR_NUM; ++i) {
                    temp.x = p.x + DISX_2[i];
                    temp.y = p.y + DISY_2[i];
                    if (set.contains(temp)) {
                        ++score;
                    }
                }
                ++ans[score];
            }
        }
        for (int i = 0; i < 5; ++i) {
            System.out.println(ans[i]);
        }
    }
}
class Point {
    int x;
    int y;
    public Point() {
        super();
    }
    public Point(int x, int y) {
        super();
        this.x = x;
        this.y = y;
    }
    @Override
    public boolean equals(Object obj) {
        if (obj instanceof Point) {
            Point p = (Point) obj;
            return (x == p.x) && (y == p.y);
        }
        return false;
    }
    @Override
    public int hashCode() {
        return Objects.hash(x, y);
    }
}