扫描透镜——网易校招编程题

import java.util.Scanner;

public class ScanGlass {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        while (sc.hasNext()) {
            int n = sc.nextInt();
            int m = sc.nextInt();
            int k = sc.nextInt();
            int[][] arr = new int[n][m];
            for (int i = 0; i < k; i++) {
                int x = sc.nextInt() - 1;
                int y = sc.nextInt() - 1;
                if (x < n && y < m) {
                    arr[x][y]++;
                }
            }
            Point firstPoint = findMaxNum(n, m, arr); // 第一次扫描到的最多蘑菇的区域
            clear(firstPoint, arr, n, m); // 清除第一次扫描过的蘑菇
            Point secondPoint = findMaxNum(n, m, arr); // 第二次扫描到的最多蘑菇的区域
            System.out.println(firstPoint.count + secondPoint.count);
        }
    }

    // 统计扫描到蘑菇的最大值
    private static Point findMaxNum(int n, int m, int[][] arr) {
        Point point = new ScanGlass().new Point();
        point.x = 0;
        point.y = 0;
        point.count = 0;
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < m; j++) {
                Point tempPoint = getNumInLocation(n, m, arr, i, j);
                if (point.count < tempPoint.count) {
                    point = tempPoint;
                }
            }
        }
        return point;
    }

    private static Point getNumInLocation(int n, int m, int[][] arr,
            int startX, int startY) {
        // 确定扫描镜的区域
        int endX;
        int endY;
        if (startX + 2 > n - 1) {
            endX = n - 1;
        } else {
            endX = startX + 2;
        }
        if (startY + 2 > m - 1) {
            endY = m -1;
        } else {
            endY = startY + 2;
        }
        // 统计该区域的蘑菇个数
        Point point = new ScanGlass().new Point();
        point.count = 0;
        point.x = startX;
        point.y = startY;
        point.endX = endX;
        point.endY = endY;

        for (int i = startX; i <= endX; i++) {
            for (int j = startY; j <= endY; j++) {
                if (arr[i][j] > 0) {
                    point.count++;
                }
            }
        }
        return point;
    }

    // 删除第一次扫描过的蘑菇
    private static void clear(Point point, int[][] arr, int n, int m) {
        for (int i = point.x; i <= point.endX; i++) {
            for (int j = point.y; j <= point.endY; j++) {
                if (arr[i][j] > 0 && i < n & j < m) {
                    arr[i][j]--;
                }
            }
        }
    }

    class Point {
        int x; // 起始x坐标
        int y; // 起始y坐标
        int count; // 区域内蘑菇总数
        int endX; // 结束x坐标
        int endY; // 结束y坐标
    }
}