bzoj 1001 狼抓兔子

裸的最小割，直接上模板就行了

 1 #define MAXN 1000010UL
 2 #include <cstdio>
 3 #include <cstring>
 4 #define INF 1e9
 5 
 6 using namespace std;
 7 
 8 int n, m, t, hd, tl, S, T, d[MAXN], sn[MAXN], q[MAXN];
 9 
10 struct Edge {
11     int hou, nt, zhi;
12 }sg[6000010];
13 
14 int Cal(int i, int j) {
15     return (i-1)*m+j;
16 }
17 
18 void Add(int x, int y, int z) {
19     sg[t] = (Edge){y, d[x], z}, d[x] = t ++;
20     sg[t] = (Edge){x, d[y], z}, d[y] = t ++;
21     return;
22 }
23 
24 bool Bfs() {
25     memset(sn, 0, sizeof(sn[0])*(T+1));
26     hd = tl = 0;
27     q[++ tl] = S, sn[S] = 1;
28     while(hd<tl) {
29         int op = q[++ hd];
30         for(int i = d[op] ; i != -1 ; i = sg[i].nt) {
31             if(sg[i].zhi&&(!sn[sg[i].hou])) {
32                 sn[sg[i].hou] = sn[op]+1;
33                 q[++ tl] = sg[i].hou;
34                 if(sg[i].hou==T) return true;
35             }
36         }
37     }
38     return false;
39 }
40 
41 int MIN(int A, int B) { return A<B?A:B; }
42 
43 int Dfs(int op, int fw) {
44     if(op==T) return fw;
45     int tmp = fw, k;
46     for(int i = d[op] ; i != -1 ; i = sg[i].nt) {
47         if(sg[i].zhi&&tmp&&sn[sg[i].hou]==sn[op]+1) {
48             k = Dfs(sg[i].hou, MIN(sg[i].zhi, tmp));
49             if(!k) {
50                 sn[sg[i].hou] = 0;
51                 continue;
52             }
53             tmp -= k;
54             sg[i].zhi -= k, sg[i^1].zhi += k;
55         }
56     }
57     return fw-tmp;
58 }
59 
60 int main() {
61     memset(d, -1, sizeof(d));
62     int x;
63     scanf("%d%d", &n, &m);
64     for(int i = 1 ; i <= n ; ++ i) {
65         for(int j = 1 ; j < m ; ++ j) {
66             scanf("%d", &x);
67             Add(Cal(i, j), Cal(i, j+1), x);
68         }
69     }
70     for(int i = 1 ; i < n ; ++ i) {
71         for(int j = 1 ; j <= m ; ++ j) {
72             scanf("%d", &x);
73             Add(Cal(i, j), Cal(i+1, j), x);
74         }
75     }
76     for(int i = 1 ; i < n ; ++ i) {
77         for(int j = 1 ; j < m ; ++ j) {
78             scanf("%d", &x);
79             Add(Cal(i, j), Cal(i+1, j+1), x);
80         }
81     }
82     S = Cal(1, 1), T = Cal(n, m);
83     int fw = 0, p;
84     while(Bfs()) while(p = Dfs(S, INF)) fw += p;
85     printf("%d", fw);
86     return 0;
87 }
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posted @ 2016-04-27 14:48  assassain  阅读(102)  评论(0)  编辑  收藏  举报