对于宫格地图寻最短路径的一个广度搜索算法

Posted 2020-06-14

 1 import java.util.ArrayDeque;
 2 import java.util.ArrayList;
 3 import java.util.HashMap;
 4 import java.util.Iterator;
 5 import java.util.Map.Entry;
 6 import java.util.Queue;
 7 
 8 public class TestPath {
 9 
10     public static void main(String[] args) {
11         int arr[][] = { { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
12                                 { 0, 0, 0, 1, 0, 0, 0, 0, 0, 0 },
13                                 { 0, 0, 0, 1, 0, 0, 0, 0, 0, 0 }, 
14                                 { 0, 0, 0, 1, 1, 0, 0, 0, 0, 0 }, 
15                                 { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
16                                 { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }, 
17                                 { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }, 
18                                 { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
19                                 { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }, 
20                                 { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 } };        
21         Queue<String> list = new ArrayDeque<>(100);
22         arr[0][0] = 1;
23         list.add("0,0,0");
24         HashMap<Integer, ArrayList<String>> map = new HashMap<>();
25         int dis = 1;
26         Iterator<String> ite = list.iterator();
27 
28         while (ite.hasNext()) {
29             String[] tm = ite.next().split(",");
30             int i = Integer.parseInt(tm[0]);
31             int j = Integer.parseInt(tm[1]);
32             if (i + 1 > 0 && i + 1 < 10 && arr[i + 1][j] != 1) {
33                 dis = Integer.parseInt(tm[2]) + 1;
34                 String p = (i + 1) + "," + j + "," + dis;
35                 arr[i + 1][j] = 1;
36                 list.add(p);
37                 if (map.get(dis) == null) {
38                     map.put(dis, new ArrayList<String>());
39                 }
40                 map.get(dis).add(p);
41             }
42             if (i - 1 > 0 && i - 1 < 10 && arr[i - 1][j] != 1) {
43                 dis = Integer.parseInt(tm[2]) + 1;
44                 String p = (i + 1) + "," + j + "," + dis;
45                 arr[i + 1][j] = 1;
46                 list.add(p);
47                 if (map.get(dis) == null) {
48                     map.put(dis, new ArrayList<String>());
49                 }
50                 map.get(dis).add(p);
51             }
52             if (j + 1 > 0 && j + 1 < 10 && arr[i][j + 1] != 1) {
53                 dis = Integer.parseInt(tm[2]) + 1;
54                 String p = i + "," + (j + 1) + "," + dis;
55                 arr[i][j + 1] = 1;
56                 list.add(p);
57                 if (map.get(dis) == null) {
58                     map.put(dis, new ArrayList<String>());
59                 }
60                 map.get(dis).add(p);
61             }
62             if (j - 1 > 0 && j - 1 < 10 && arr[i][j - 1] != 1) {
63                 dis = Integer.parseInt(tm[2]) + 1;
64                 String p = i + "," + (j + 1) + "," + dis;
65                 arr[i][j + 1] = 1;
66                 list.add(p);
67                 if (map.get(dis) == null) {
68                     map.put(dis, new ArrayList<String>());
69                 }
70                 map.get(dis).add(p);
71             }
72             ite.remove();
73             ite = list.iterator();
74         }
75         for (int i = 0; i < map.get(3).size(); i++) {
76             System.out.println(map.get(3).get(i));
77         }
78         for (Entry<Integer, ArrayList<String>> m: map.entrySet()) {
79             for (String str : m.getValue()) {
80                 if (str.startsWith("2,4")) {
81                     System.out.println(str);
82                 }
83             }
84         }
85     }
86 
87 }

记录了各个点到(0,0)点的距离，其中数组中值为1的点是不可通过的点。