BZOJ1736 [Usaco2005 jan]The Wedding Juicer 婚宴的榨汁机

从外面一点一点往里面拓展(floodfill)，每次找出最小的一个点，计算它对答案的贡献就好了。。。

找最小的点的话，直接pq就行

 1 /**************************************************************
 2     Problem: 1736
 3     User: rausen
 4     Language: C++
 5     Result: Accepted
 6     Time:196 ms
 7     Memory:2116 kb
 8 ****************************************************************/
 9
10 #include <cstdio>
11 #include <queue>
12
13 using namespace std;
14 typedef long long ll;
15 const int N = 305;
16 const int dx[] = {0, 0, 1, -1};
17 const int dy[] = {1, -1, 0, 0};
18
19 inline int read();
20
21 struct data {
22     int x, y, h;
23     data(int _x = 0, int _y = 0, int _h = 0) : x(_x), y(_y), h(_h) {}
24
25     inline bool operator < (const data &d) const {
26         return h > d.h;
27     }
28 };
29
30 int n, m;
31 int mp[N][N], v[N][N];
32 priority_queue <data> h;
33
34 inline ll work(){
35     ll res = 0;
36     int x, y, k;
37     data now;
38     while (!h.empty()) {
39         now = h.top(), h.pop();
40         for (k = 0; k < 4; ++k) {
41             x = now.x + dx[k], y = now.y + dy[k];
42             if (x <= 0 || y <= 0 || x > n || y > m || v[x][y]) continue;
43             v[x][y] = 1;
44             if (mp[x][y] < now.h)
45                 res += now.h - mp[x][y], mp[x][y] = now.h;
46             h.push(data(x, y, mp[x][y]));
47         }
48     }
49     return res;
50 }
51
52 int main() {
53     int i, j;
54     m = read(), n = read();
55     for (i = 1; i <= n; ++i)
56         for (j = 1; j <= m; ++j) mp[i][j] = read();
57     for (i = 1; i <= n; ++i)
58         for (j = 1; j <= m; ++j)
59             if (i == 1 || j == 1 || i == n || j == m)
60                 h.push(data(i, j, mp[i][j])), v[i][j] = 1;
61     printf("%lld\n", work());
62     return 0;
63 }
64
65 inline int read() {
66     static int x;
67     static char ch;
68     x = 0, ch = getchar();
69     while (ch < ‘0‘ || ‘9‘ < ch)
70         ch = getchar();
71     while (‘0‘ <= ch && ch <= ‘9‘) {
72         x = x * 10 + ch - ‘0‘;
73         ch = getchar();
74     }
75     return x;
76 }