ZOJ 1107FatMouse and Cheese(BFS）

 1 #include <iostream>
 2 #include <cstdio>
 3 #include <queue>
 4 #include <cstring>
 5 #include <algorithm>
 6 using namespace std;
 7 const int Max = 550 + 10;
 8 const int INF = 0x3f3f3f3f;
 9 int g[Max][Max], dp[Max][Max];
10 int n, k;
11 int gx[4] = {0, 0, 1, -1};
12 int gy[4] = {1, -1, 0, 0};
13 struct Node
14 {
15     int x, y;
16 
17 };
18 void bfs(int x, int y)
19 {
20     Node node;
21     node.x = x;
22     node.y = y;
23     dp[x][y] = g[x][y];
24     queue<Node> que;
25     que.push(node);
26     int maxn = -INF;
27     while (!que.empty())
28     {
29         node = que.front();
30         que.pop();
31         if (dp[node.x][node.y] > maxn)
32             maxn = dp[node.x][node.y];
33         for (int i = 0; i < 4; i++)
34         {
35             for (int j = 1; j <= k; j++)
36             {
37                 int fx = node.x + gx[i] * j;
38                 int fy = node.y + gy[i] * j;
39                 if (fx >= 1 && fy >= 1 && fx <= n && fy <= n && g[fx][fy] > g[node.x][node.y])
40                 {
41                     if (dp[fx][fy] < g[fx][fy] + dp[node.x][node.y])
42                     {
43                         dp[fx][fy] = g[fx][fy] +  dp[node.x][node.y];
44                         Node temp;
45                         temp.x = fx;
46                         temp.y = fy;
47                         que.push(temp);
48                     }
49                 }
50             }
51         }
52     }
53     printf("%d\n", maxn);
54 }
55 int main()
56 {
57     while (scanf("%d%d", &n, &k) != EOF)
58     {
59         if (n == -1 && k == -1)
60             break;
61         for (int i = 1; i <= n; i++)
62             for (int j = 1; j <= n; j++)
63                 scanf("%d", &g[i][j]);
64         memset(dp, 0, sizeof(dp));
65         bfs(1, 1);
66     }
67     return 0;
68 }