最大流模板 ISAP

邻接矩阵:

 1 #include<stdio.h>
 2 #include<string.h>
 3 #include<stdlib.h>
 4 #define MIN(a,b) (a)<(b)?(a):(b)
 5 const int M = 110;
 6 const int inf = 0x3fffffff;
 7 int n, m, A[1010], pre[1010];
 8 int remain[M][M], h[M], vh[M], S, T, N;39 int DFS( int u, int flow ) 
40 {
41     if( u == T ) return flow;//找到增广路
42     int tmp = h[u]+1, sum = flow; //更新当前点层数
43     for(int v = 0; v < N; v++)
44     {
45         if( remain[u][v] && h[u] == h[v]+1 ) //允许弧,且一层差别
46         {
47             int p = DFS( v, MIN( sum, remain[u][v]) );
48             remain[u][v] -= p; remain[v][u] += p; sum -= p; //更新残留网络
49             if( sum == 0 || h[S] == N ) return flow-sum;    
50         }
51     }
52     for(int v = 0; v < N; v++)
53         if( remain[u][v] )    
54             tmp = MIN( tmp, h[v] );
55     if( !( --vh[ h[u] ] ) ) h[S] = N; //间隙优化,当出现断层即可判定无增广路
56     else    ++vh[ h[u] = tmp+1 ]; 
57     return flow-sum;
58 }
59 void sap()
60 {
61     int maxflow = 0;
62     memset( h, 0, sizeof(h));
63     memset( vh, 0, sizeof(vh));
64     vh[S] = N; //0层节点数量为N
65     while( h[S] < N )    maxflow += DFS( S, inf );
66     printf("%d\n", maxflow );
67 }

 

静态链表:

 1 #include<cstdio>
 2 #include<cstdlib>
 3 #include<cstring>
 4 #include<string>
 5 #include<algorithm>
 6 #include<vector>
 7 using namespace std;
 8 
 9 const int inf = 0x3f3f3f3f;
10 int n, m, K;
11 int N, M, S, T;
12 bool mp[100][100];
13 int vh[500], h[500];
14 
15 struct node{
16     int v, f, nxt;
17 }edge[250000];
18 int head[500], idx;
19 
20 void addedge(int u,int v,int f){
21     edge[idx].v = v; edge[idx].f = f;
22     edge[idx].nxt = head[u]; head[u] = idx++;
23     
24     edge[idx].v = u; edge[idx].f = 0;
25     edge[idx].nxt = head[v]; head[v] = idx++;
26 }
27 void CreateGraph(int L){
28     idx = 0;
29     memset(head,-1,sizeof(head));
30 
31     for(int x = 1; x <= n; x++){
32         addedge( S, x, L );
33         for(int y = 1; y <= m; y++){
34             if( mp[x][y] ) addedge(x,n+y,1);
35             else addedge(x,m+n+y,1); 
36         }
37     }
38     for(int y = 1; y <= m; y++){
39         addedge( n+y, n+2*m+y , n );
40         addedge( n+m+y, n+2*m+y, K );
41         addedge( n+2*m+y, T, L );
42     }    
43 }
44 int dfs(int u,int flow){
45     if( u == T ) return flow;
46     int tmp = h[u]+1, sum = flow;
47     for(int i = head[u]; ~i; i = edge[i].nxt ){
48         if( edge[i].f && (h[edge[i].v]+1==h[u]) ){
49             int p = dfs( edge[i].v , min(sum,edge[i].f) );    
50             edge[i].f -= p; edge[i^1].f += p; sum -= p;
51             if( sum == 0 || h[S] == N ) return flow-sum;
52         }    
53     }
54     for(int i = head[u]; ~i; i = edge[i].nxt )        
55         if( edge[i].f ) tmp = min( tmp, h[ edge[i].v ] );
56     if( --vh[ h[u] ] == 0 ) h[S] = N;
57     else ++vh[ h[u]=tmp+1 ];
58     return flow-sum;
59 }
60 int SAP(){
61     int maxflow = 0;
62     memset(vh,0,sizeof(vh));
63     memset(h,0,sizeof(h));
64     vh[S] = N;
65     while( h[S] < N ) maxflow += dfs( S, inf );
66     return maxflow;
67 }

 

posted @ 2013-05-25 10:23  yefeng1627  阅读(303)  评论(0编辑  收藏  举报

Launch CodeCogs Equation Editor