枚举 + 广度搜索 ----炸弹人

package com.xjj.Ah;

import java.util.LinkedList;

/*---枚举 + 广度搜索 ----炸弹人----
 * 1. 炸弹能到达的地方最多能炸死的敌人数
 * 2. 用枚举法来获得每个空格放置炸弹能炸死的敌人数，用广度搜索法来获得能达到的地方
 * 3. 用一个队列来保存能达到的地方，入队出队来依次深入...,book[][] 标记是否已经入队
 * 
 * 
 * */
public class Ah_4_4 {
	static int N = 13;
	static int M = 13;
	class Dis{
		int x;
		int y;
	}
	//‘#’为墙，‘H’为空格，‘G’为敌人
	static char[][] a = {{'#','#','#','#','#','#','#','#','#','#','#','#','#'},
			  			 {'#','G','G','H','G','G','G','#','G','G','G','H','#'},
			  			 {'#','#','#','H','#','G','#','G','#','G','#','G','#'},
			  			 {'#','H','H','H','H','H','H','H','#','H','H','G','#'},
			  			 {'#','G','#','H','#','#','#','H','#','G','#','G','#'},
			  			 {'#','G','G','H','G','G','G','H','#','H','G','G','#'},
			  			 {'#','G','#','H','#','G','#','H','#','H','#','H','#'},
			  			 {'#','#','G','H','H','H','G','H','H','H','H','H','#'},
			  			 {'#','G','#','H','#','G','#','#','#','H','#','G','#'},
			  			 {'#','H','H','H','G','#','G','G','G','H','G','G','#'},
			  			 {'#','G','#','H','#','G','#','G','#','H','#','G','#'},
			  			 {'#','G','G','H','G','G','G','#','G','H','G','G','#'},
			  			 {'#','#','#','#','#','#','#','#','#','#','#','#','#'},
			  			};
	
	//返回该点可炸死敌人的数目，枚举法
	public int getNum(int i, int j){
		int sum=0,x,y;
		
		//向上统计
		x = i;
		y = j;
		while(a[x][y] != '#'){
			if (a[x][y] == 'G') 
				sum++;
			x--;
		}
		//向下统计
		x = i;
		y = j;
		while(a[x][y] != '#'){
			if (a[x][y] == 'G') 
				sum++;
			x++;
		}
		//向左统计
		x = i;
		y = j;
		while(a[x][y] != '#'){
			if (a[x][y] == 'G') 
				sum++;
			y--;
		}
		//向右统计
		x = i;
		y = j;
		while(a[x][y] != '#'){
			if (a[x][y] == 'G') 
				sum++;
			y++;
		}
		return sum;
	}
	
	//广度搜索法
	public void bfs(int startx, int starty){
		int[][] dir = {{0,1},{1,0},{0,-1},{-1,0}};			//方向矩阵-右下左上
		int[][] book = new int[N][M];						//标记是否入队
		int max = 0,sum,X = 0,Y = 0;
		
		Dis d = new Dis();						//新的坐标入队
		d.x = startx;
		d.y = starty;
		LinkedList list = new LinkedList<>();
		list.add(d);
		book[startx][starty] = 1;				//标记入队
		
		//直到队列为空
		while(!list.isEmpty()){				
			//获得头结点能炸死的敌人数
			sum = getNum(list.getFirst().x, list.getFirst().y);
			//更新
			if (sum > max) {
				max = sum;
				X = list.getFirst().x;
				Y = list.getFirst().y;
			}
			//枚举四个方向
			for(int k = 0; k <= 3; k++){
				//先向右移动
				int x = list.getFirst().x + dir[k][0];
				int y = list.getFirst().y + dir[k][1];
				
				//判断是否出界
				if (x > N-1 || x < 1 || y > M-1 || y < 1) {
					continue;
				}
				
				//为空格且未入队
				if (a[x][y] == 'H' && book[x][y] == 0) {
					d = new Dis();
					d.x = x;
					d.y = y;
					list.add(d);
					book[x][y] = 1;
					
				}
			}
			list.removeFirst();//千万不能忘记，移除头结点才能往下扩展

		}
		
		System.out.println("坐标为: " + X + " " + Y);
		System.out.println("最大敌人为: " + max);
	}

	public static void main(String[] args) {
		Ah_4_4 ah = new Ah_4_4();
		ah.bfs(3, 3);		

	}

}