1 // -*- C++ -*- |
1 // -*- C++ -*- |
2 /* |
2 /* |
3 preflow.h |
|
4 by jacint. |
|
5 Heuristics: |
3 Heuristics: |
6 2 phase |
4 2 phase |
7 gap |
5 gap |
8 list 'level_list' on the nodes on level i implemented by hand |
6 list 'level_list' on the nodes on level i implemented by hand |
9 stack 'active' on the active nodes on level i implemented by hand |
7 stack 'active' on the active nodes on level i implemented by hand |
10 runs heuristic 'highest label' for H1*n relabels |
8 runs heuristic 'highest label' for H1*n relabels |
11 runs heuristic 'bound decrease' for H0*n relabels, starts with 'highest label' |
9 runs heuristic 'bound decrease' for H0*n relabels, starts with 'highest label' |
12 |
10 |
13 Parameters H0 and H1 are initialized to 20 and 10. |
11 Parameters H0 and H1 are initialized to 20 and 10. |
14 |
12 |
15 The best preflow I could ever write. |
13 Constructors: |
16 |
14 |
17 The constructor runs the algorithm. |
15 Preflow(Graph, Node, Node, CapMap, FlowMap) |
18 |
16 |
19 Members: |
17 Members: |
20 |
18 |
21 T maxFlow() : returns the value of a maximum flow |
19 void run() |
22 |
20 |
23 T flowOnEdge(EdgeIt e) : for a fixed maximum flow x it returns x(e) |
21 T flowValue() : returns the value of a maximum flow |
24 |
|
25 FlowMap Flow() : returns the fixed maximum flow x |
|
26 |
22 |
27 void minMinCut(CutMap& M) : sets M to the characteristic vector of the |
23 void minMinCut(CutMap& M) : sets M to the characteristic vector of the |
28 minimum min cut. M should be a map of bools initialized to false. |
24 minimum min cut. M should be a map of bools initialized to false. |
29 |
25 |
30 void maxMinCut(CutMap& M) : sets M to the characteristic vector of the |
26 void maxMinCut(CutMap& M) : sets M to the characteristic vector of the |
33 void minCut(CutMap& M) : sets M to the characteristic vector of |
29 void minCut(CutMap& M) : sets M to the characteristic vector of |
34 a min cut. M should be a map of bools initialized to false. |
30 a min cut. M should be a map of bools initialized to false. |
35 |
31 |
36 */ |
32 */ |
37 |
33 |
38 #ifndef PREFLOW_H |
34 #ifndef HUGO_PREFLOW_H |
39 #define PREFLOW_H |
35 #define HUGO_PREFLOW_H |
40 |
36 |
41 #define H0 20 |
37 #define H0 20 |
42 #define H1 1 |
38 #define H1 1 |
43 |
39 |
44 #include <vector> |
40 #include <vector> |
45 #include <queue> |
41 #include <queue> |
46 |
|
47 #include <time_measure.h> |
|
48 |
42 |
49 namespace hugo { |
43 namespace hugo { |
50 |
44 |
51 template <typename Graph, typename T, |
45 template <typename Graph, typename T, |
52 typename FlowMap=typename Graph::EdgeMap<T>, |
46 typename FlowMap=typename Graph::EdgeMap<T>, |
53 typename CapMap=typename Graph::EdgeMap<T> > |
47 typename CapMap=typename Graph::EdgeMap<T> > |
54 class preflow { |
48 class Preflow { |
55 |
49 |
|
50 typedef typename Graph::Node Node; |
|
51 typedef typename Graph::Edge Edge; |
56 typedef typename Graph::NodeIt NodeIt; |
52 typedef typename Graph::NodeIt NodeIt; |
57 typedef typename Graph::EdgeIt EdgeIt; |
|
58 typedef typename Graph::EachNodeIt EachNodeIt; |
|
59 typedef typename Graph::OutEdgeIt OutEdgeIt; |
53 typedef typename Graph::OutEdgeIt OutEdgeIt; |
60 typedef typename Graph::InEdgeIt InEdgeIt; |
54 typedef typename Graph::InEdgeIt InEdgeIt; |
61 |
55 |
62 Graph& G; |
56 const Graph& G; |
63 NodeIt s; |
57 Node s; |
64 NodeIt t; |
58 Node t; |
65 FlowMap flow; |
59 FlowMap& flow; |
66 CapMap& capacity; |
60 const CapMap& capacity; |
67 T value; |
61 T value; |
68 |
62 |
69 public: |
63 public: |
70 double time; |
64 Preflow(Graph& _G, Node _s, Node _t, CapMap& _capacity, FlowMap& _flow ) : |
71 preflow(Graph& _G, NodeIt _s, NodeIt _t, CapMap& _capacity ) : |
65 G(_G), s(_s), t(_t), flow(_flow), capacity(_capacity) {} |
72 G(_G), s(_s), t(_t), flow(_G, 0), capacity(_capacity) |
66 |
73 { |
67 |
|
68 void run() { |
74 |
69 |
75 bool phase=0; //phase 0 is the 1st phase, phase 1 is the 2nd |
70 bool phase=0; //phase 0 is the 1st phase, phase 1 is the 2nd |
76 int n=G.nodeNum(); |
71 int n=G.nodeNum(); |
77 int heur0=(int)(H0*n); //time while running 'bound decrease' |
72 int heur0=(int)(H0*n); //time while running 'bound decrease' |
78 int heur1=(int)(H1*n); //time while running 'highest label' |
73 int heur1=(int)(H1*n); //time while running 'highest label' |
92 int b=k; //bound on the highest level under n of an active node |
87 int b=k; //bound on the highest level under n of an active node |
93 |
88 |
94 typename Graph::NodeMap<int> level(G,n); |
89 typename Graph::NodeMap<int> level(G,n); |
95 typename Graph::NodeMap<T> excess(G); |
90 typename Graph::NodeMap<T> excess(G); |
96 |
91 |
97 std::vector<NodeIt> active(n); |
92 std::vector<Node> active(n,INVALID); |
98 typename Graph::NodeMap<NodeIt> next(G); |
93 typename Graph::NodeMap<Node> next(G,INVALID); |
99 //Stack of the active nodes in level i < n. |
94 //Stack of the active nodes in level i < n. |
100 //We use it in both phases. |
95 //We use it in both phases. |
101 |
96 |
102 typename Graph::NodeMap<NodeIt> left(G); |
97 typename Graph::NodeMap<Node> left(G,INVALID); |
103 typename Graph::NodeMap<NodeIt> right(G); |
98 typename Graph::NodeMap<Node> right(G,INVALID); |
104 std::vector<NodeIt> level_list(n); |
99 std::vector<Node> level_list(n,INVALID); |
105 /* |
100 /* |
106 List of the nodes in level i<n. |
101 List of the nodes in level i<n. |
107 */ |
102 */ |
108 |
103 |
109 /*Reverse_bfs from t, to find the starting level.*/ |
104 /*Reverse_bfs from t, to find the starting level.*/ |
110 level.set(t,0); |
105 level.set(t,0); |
111 std::queue<NodeIt> bfs_queue; |
106 std::queue<Node> bfs_queue; |
112 bfs_queue.push(t); |
107 bfs_queue.push(t); |
113 |
108 |
114 while (!bfs_queue.empty()) { |
109 while (!bfs_queue.empty()) { |
115 |
110 |
116 NodeIt v=bfs_queue.front(); |
111 Node v=bfs_queue.front(); |
117 bfs_queue.pop(); |
112 bfs_queue.pop(); |
118 int l=level.get(v)+1; |
113 int l=level[v]+1; |
119 |
114 |
120 for(InEdgeIt e=G.template first<InEdgeIt>(v); e.valid(); ++e) { |
115 InEdgeIt e; |
121 NodeIt w=G.tail(e); |
116 for(G.first(e,v); G.valid(e); G.next(e)) { |
122 if ( level.get(w) == n && w != s ) { |
117 Node w=G.tail(e); |
|
118 if ( level[w] == n && w != s ) { |
123 bfs_queue.push(w); |
119 bfs_queue.push(w); |
124 NodeIt first=level_list[l]; |
120 Node first=level_list[l]; |
125 if ( first != 0 ) left.set(first,w); |
121 if ( G.valid(first) ) left.set(first,w); |
126 right.set(w,first); |
122 right.set(w,first); |
127 level_list[l]=w; |
123 level_list[l]=w; |
128 level.set(w, l); |
124 level.set(w, l); |
129 } |
125 } |
130 } |
126 } |
132 |
128 |
133 level.set(s,n); |
129 level.set(s,n); |
134 |
130 |
135 |
131 |
136 /* Starting flow. It is everywhere 0 at the moment. */ |
132 /* Starting flow. It is everywhere 0 at the moment. */ |
137 for(OutEdgeIt e=G.template first<OutEdgeIt>(s); e.valid(); ++e) |
133 OutEdgeIt e; |
|
134 for(G.first(e,s); G.valid(e); G.next(e)) |
138 { |
135 { |
139 T c=capacity.get(e); |
136 T c=capacity[e]; |
140 if ( c == 0 ) continue; |
137 if ( c == 0 ) continue; |
141 NodeIt w=G.head(e); |
138 Node w=G.head(e); |
142 if ( level.get(w) < n ) { |
139 if ( level[w] < n ) { |
143 if ( excess.get(w) == 0 && w!=t ) { |
140 if ( excess[w] == 0 && w!=t ) { |
144 next.set(w,active[level.get(w)]); |
141 next.set(w,active[level[w]]); |
145 active[level.get(w)]=w; |
142 active[level[w]]=w; |
146 } |
143 } |
147 flow.set(e, c); |
144 flow.set(e, c); |
148 excess.set(w, excess.get(w)+c); |
145 excess.set(w, excess[w]+c); |
149 } |
146 } |
150 } |
147 } |
151 |
148 |
152 /* |
149 /* |
153 End of preprocessing |
150 End of preprocessing |
166 if ( !what_heur && !end && k > 0 ) { |
163 if ( !what_heur && !end && k > 0 ) { |
167 b=k; |
164 b=k; |
168 end=true; |
165 end=true; |
169 } else { |
166 } else { |
170 phase=1; |
167 phase=1; |
171 time=currTime(); |
|
172 level.set(s,0); |
168 level.set(s,0); |
173 std::queue<NodeIt> bfs_queue; |
169 std::queue<Node> bfs_queue; |
174 bfs_queue.push(s); |
170 bfs_queue.push(s); |
175 |
171 |
176 while (!bfs_queue.empty()) { |
172 while (!bfs_queue.empty()) { |
177 |
173 |
178 NodeIt v=bfs_queue.front(); |
174 Node v=bfs_queue.front(); |
179 bfs_queue.pop(); |
175 bfs_queue.pop(); |
180 int l=level.get(v)+1; |
176 int l=level[v]+1; |
181 |
177 |
182 for(InEdgeIt e=G.template first<InEdgeIt>(v); e.valid(); ++e) { |
178 InEdgeIt e; |
183 if ( capacity.get(e) == flow.get(e) ) continue; |
179 for(G.first(e,v); G.valid(e); G.next(e)) { |
184 NodeIt u=G.tail(e); |
180 if ( capacity[e] == flow[e] ) continue; |
185 if ( level.get(u) >= n ) { |
181 Node u=G.tail(e); |
|
182 if ( level[u] >= n ) { |
186 bfs_queue.push(u); |
183 bfs_queue.push(u); |
187 level.set(u, l); |
184 level.set(u, l); |
188 if ( excess.get(u) > 0 ) { |
185 if ( excess[u] > 0 ) { |
189 next.set(u,active[l]); |
186 next.set(u,active[l]); |
190 active[l]=u; |
187 active[l]=u; |
191 } |
188 } |
192 } |
189 } |
193 } |
190 } |
194 |
191 |
195 for(OutEdgeIt e=G.template first<OutEdgeIt>(v); e.valid(); ++e) { |
192 OutEdgeIt f; |
196 if ( 0 == flow.get(e) ) continue; |
193 for(G.first(f,v); G.valid(f); G.next(f)) { |
197 NodeIt u=G.head(e); |
194 if ( 0 == flow[f] ) continue; |
198 if ( level.get(u) >= n ) { |
195 Node u=G.head(f); |
|
196 if ( level[u] >= n ) { |
199 bfs_queue.push(u); |
197 bfs_queue.push(u); |
200 level.set(u, l); |
198 level.set(u, l); |
201 if ( excess.get(u) > 0 ) { |
199 if ( excess[u] > 0 ) { |
202 next.set(u,active[l]); |
200 next.set(u,active[l]); |
203 active[l]=u; |
201 active[l]=u; |
204 } |
202 } |
205 } |
203 } |
206 } |
204 } |
209 } |
207 } |
210 |
208 |
211 } |
209 } |
212 |
210 |
213 |
211 |
214 if ( active[b] == 0 ) --b; |
212 if ( !G.valid(active[b]) ) --b; |
215 else { |
213 else { |
216 end=false; |
214 end=false; |
217 |
215 |
218 NodeIt w=active[b]; |
216 Node w=active[b]; |
219 active[b]=next.get(w); |
217 active[b]=next[w]; |
220 int lev=level.get(w); |
218 int lev=level[w]; |
221 T exc=excess.get(w); |
219 T exc=excess[w]; |
222 int newlevel=n; //bound on the next level of w |
220 int newlevel=n; //bound on the next level of w |
223 |
221 |
224 for(OutEdgeIt e=G.template first<OutEdgeIt>(w); e.valid(); ++e) { |
222 OutEdgeIt e; |
225 |
223 for(G.first(e,w); G.valid(e); G.next(e)) { |
226 if ( flow.get(e) == capacity.get(e) ) continue; |
224 |
227 NodeIt v=G.head(e); |
225 if ( flow[e] == capacity[e] ) continue; |
|
226 Node v=G.head(e); |
228 //e=wv |
227 //e=wv |
229 |
228 |
230 if( lev > level.get(v) ) { |
229 if( lev > level[v] ) { |
231 /*Push is allowed now*/ |
230 /*Push is allowed now*/ |
232 |
231 |
233 if ( excess.get(v)==0 && v!=t && v!=s ) { |
232 if ( excess[v]==0 && v!=t && v!=s ) { |
234 int lev_v=level.get(v); |
233 int lev_v=level[v]; |
235 next.set(v,active[lev_v]); |
234 next.set(v,active[lev_v]); |
236 active[lev_v]=v; |
235 active[lev_v]=v; |
237 } |
236 } |
238 |
237 |
239 T cap=capacity.get(e); |
238 T cap=capacity[e]; |
240 T flo=flow.get(e); |
239 T flo=flow[e]; |
241 T remcap=cap-flo; |
240 T remcap=cap-flo; |
242 |
241 |
243 if ( remcap >= exc ) { |
242 if ( remcap >= exc ) { |
244 /*A nonsaturating push.*/ |
243 /*A nonsaturating push.*/ |
245 |
244 |
246 flow.set(e, flo+exc); |
245 flow.set(e, flo+exc); |
247 excess.set(v, excess.get(v)+exc); |
246 excess.set(v, excess[v]+exc); |
248 exc=0; |
247 exc=0; |
249 break; |
248 break; |
250 |
249 |
251 } else { |
250 } else { |
252 /*A saturating push.*/ |
251 /*A saturating push.*/ |
253 |
252 |
254 flow.set(e, cap); |
253 flow.set(e, cap); |
255 excess.set(v, excess.get(v)+remcap); |
254 excess.set(v, excess[v]+remcap); |
256 exc-=remcap; |
255 exc-=remcap; |
257 } |
256 } |
258 } else if ( newlevel > level.get(v) ){ |
257 } else if ( newlevel > level[v] ){ |
259 newlevel = level.get(v); |
258 newlevel = level[v]; |
260 } |
259 } |
261 |
260 |
262 } //for out edges wv |
261 } //for out edges wv |
263 |
262 |
264 |
263 |
265 if ( exc > 0 ) { |
264 if ( exc > 0 ) { |
266 for( InEdgeIt e=G.template first<InEdgeIt>(w); e.valid(); ++e) { |
265 InEdgeIt e; |
267 |
266 for(G.first(e,w); G.valid(e); G.next(e)) { |
268 if( flow.get(e) == 0 ) continue; |
267 |
269 NodeIt v=G.tail(e); |
268 if( flow[e] == 0 ) continue; |
|
269 Node v=G.tail(e); |
270 //e=vw |
270 //e=vw |
271 |
271 |
272 if( lev > level.get(v) ) { |
272 if( lev > level[v] ) { |
273 /*Push is allowed now*/ |
273 /*Push is allowed now*/ |
274 |
274 |
275 if ( excess.get(v)==0 && v!=t && v!=s ) { |
275 if ( excess[v]==0 && v!=t && v!=s ) { |
276 int lev_v=level.get(v); |
276 int lev_v=level[v]; |
277 next.set(v,active[lev_v]); |
277 next.set(v,active[lev_v]); |
278 active[lev_v]=v; |
278 active[lev_v]=v; |
279 } |
279 } |
280 |
280 |
281 T flo=flow.get(e); |
281 T flo=flow[e]; |
282 |
282 |
283 if ( flo >= exc ) { |
283 if ( flo >= exc ) { |
284 /*A nonsaturating push.*/ |
284 /*A nonsaturating push.*/ |
285 |
285 |
286 flow.set(e, flo-exc); |
286 flow.set(e, flo-exc); |
287 excess.set(v, excess.get(v)+exc); |
287 excess.set(v, excess[v]+exc); |
288 exc=0; |
288 exc=0; |
289 break; |
289 break; |
290 } else { |
290 } else { |
291 /*A saturating push.*/ |
291 /*A saturating push.*/ |
292 |
292 |
293 excess.set(v, excess.get(v)+flo); |
293 excess.set(v, excess[v]+flo); |
294 exc-=flo; |
294 exc-=flo; |
295 flow.set(e,0); |
295 flow.set(e,0); |
296 } |
296 } |
297 } else if ( newlevel > level.get(v) ) { |
297 } else if ( newlevel > level[v] ) { |
298 newlevel = level.get(v); |
298 newlevel = level[v]; |
299 } |
299 } |
300 } //for in edges vw |
300 } //for in edges vw |
301 |
301 |
302 } // if w still has excess after the out edge for cycle |
302 } // if w still has excess after the out edge for cycle |
303 |
303 |
316 next.set(w,active[newlevel]); |
316 next.set(w,active[newlevel]); |
317 active[newlevel]=w; |
317 active[newlevel]=w; |
318 b=newlevel; |
318 b=newlevel; |
319 } else { |
319 } else { |
320 //unlacing starts |
320 //unlacing starts |
321 NodeIt right_n=right.get(w); |
321 Node right_n=right[w]; |
322 NodeIt left_n=left.get(w); |
322 Node left_n=left[w]; |
323 |
323 |
324 if ( right_n != 0 ) { |
324 if ( G.valid(right_n) ) { |
325 if ( left_n != 0 ) { |
325 if ( G.valid(left_n) ) { |
326 right.set(left_n, right_n); |
326 right.set(left_n, right_n); |
327 left.set(right_n, left_n); |
327 left.set(right_n, left_n); |
328 } else { |
328 } else { |
329 level_list[lev]=right_n; |
329 level_list[lev]=right_n; |
330 left.set(right_n, 0); |
330 left.set(right_n, INVALID); |
331 } |
331 } |
332 } else { |
332 } else { |
333 if ( left_n != 0 ) { |
333 if ( G.valid(left_n) ) { |
334 right.set(left_n, 0); |
334 right.set(left_n, INVALID); |
335 } else { |
335 } else { |
336 level_list[lev]=0; |
336 level_list[lev]=INVALID; |
337 |
|
338 } |
337 } |
339 } |
338 } |
340 //unlacing ends |
339 //unlacing ends |
341 |
340 |
342 //gapping starts |
341 //gapping starts |
343 if ( level_list[lev]==0 ) { |
342 if ( !G.valid(level_list[lev]) ) { |
344 |
343 |
345 for (int i=lev; i!=k ; ) { |
344 for (int i=lev; i!=k ; ) { |
346 NodeIt v=level_list[++i]; |
345 Node v=level_list[++i]; |
347 while ( v != 0 ) { |
346 while ( G.valid(v) ) { |
348 level.set(v,n); |
347 level.set(v,n); |
349 v=right.get(v); |
348 v=right[v]; |
350 } |
349 } |
351 level_list[i]=0; |
350 level_list[i]=INVALID; |
352 if ( !what_heur ) active[i]=0; |
351 if ( !what_heur ) active[i]=INVALID; |
353 } |
352 } |
354 |
353 |
355 level.set(w,n); |
354 level.set(w,n); |
356 b=lev-1; |
355 b=lev-1; |
357 k=b; |
356 k=b; |
363 level.set(w,++newlevel); |
362 level.set(w,++newlevel); |
364 next.set(w,active[newlevel]); |
363 next.set(w,active[newlevel]); |
365 active[newlevel]=w; |
364 active[newlevel]=w; |
366 if ( what_heur ) b=newlevel; |
365 if ( what_heur ) b=newlevel; |
367 if ( k < newlevel ) ++k; |
366 if ( k < newlevel ) ++k; |
368 NodeIt first=level_list[newlevel]; |
367 Node first=level_list[newlevel]; |
369 if ( first != 0 ) left.set(first,w); |
368 if ( G.valid(first) ) left.set(first,w); |
370 right.set(w,first); |
369 right.set(w,first); |
371 left.set(w,0); |
370 left.set(w,INVALID); |
372 level_list[newlevel]=w; |
371 level_list[newlevel]=w; |
373 } |
372 } |
374 } |
373 } |
375 |
374 |
376 |
375 |
409 |
408 |
410 /* |
409 /* |
411 Returns the maximum value of a flow. |
410 Returns the maximum value of a flow. |
412 */ |
411 */ |
413 |
412 |
414 T maxFlow() { |
413 T flowValue() { |
415 return value; |
414 return value; |
416 } |
415 } |
417 |
|
418 |
|
419 |
|
420 /* |
|
421 For the maximum flow x found by the algorithm, |
|
422 it returns the flow value on edge e, i.e. x(e). |
|
423 */ |
|
424 |
|
425 T flowOnEdge(EdgeIt e) { |
|
426 return flow.get(e); |
|
427 } |
|
428 |
|
429 |
416 |
430 |
417 |
431 FlowMap Flow() { |
418 FlowMap Flow() { |
432 return flow; |
419 return flow; |
433 } |
420 } |
434 |
421 |
435 |
422 |
436 |
423 |
437 void Flow(FlowMap& _flow ) { |
424 void Flow(FlowMap& _flow ) { |
438 for(EachNodeIt v=G.template first<EachNodeIt>() ; v.valid(); ++v) |
425 NodeIt v; |
439 _flow.set(v,flow.get(v)); |
426 for(G.first(v) ; G.valid(v); G.next(v)) |
440 } |
427 _flow.set(v,flow[v]); |
|
428 } |
441 |
429 |
442 |
430 |
443 |
431 |
444 /* |
432 /* |
445 Returns the minimum min cut, by a bfs from s in the residual graph. |
433 Returns the minimum min cut, by a bfs from s in the residual graph. |
446 */ |
434 */ |
447 |
435 |
448 template<typename _CutMap> |
436 template<typename _CutMap> |
449 void minMinCut(_CutMap& M) { |
437 void minMinCut(_CutMap& M) { |
450 |
438 |
451 std::queue<NodeIt> queue; |
439 std::queue<Node> queue; |
452 |
440 |
453 M.set(s,true); |
441 M.set(s,true); |
454 queue.push(s); |
442 queue.push(s); |
455 |
443 |
456 while (!queue.empty()) { |
444 while (!queue.empty()) { |
457 NodeIt w=queue.front(); |
445 Node w=queue.front(); |
458 queue.pop(); |
446 queue.pop(); |
459 |
447 |
460 for(OutEdgeIt e=G.template first<OutEdgeIt>(w) ; e.valid(); ++e) { |
448 OutEdgeIt e; |
461 NodeIt v=G.head(e); |
449 for(G.first(e,w) ; G.valid(e); G.next(e)) { |
462 if (!M.get(v) && flow.get(e) < capacity.get(e) ) { |
450 Node v=G.head(e); |
|
451 if (!M[v] && flow[e] < capacity[e] ) { |
463 queue.push(v); |
452 queue.push(v); |
464 M.set(v, true); |
453 M.set(v, true); |
465 } |
454 } |
466 } |
455 } |
467 |
456 |
468 for(InEdgeIt e=G.template first<InEdgeIt>(w) ; e.valid(); ++e) { |
457 InEdgeIt f; |
469 NodeIt v=G.tail(e); |
458 for(G.first(f,w) ; G.valid(f); G.next(f)) { |
470 if (!M.get(v) && flow.get(e) > 0 ) { |
459 Node v=G.tail(f); |
|
460 if (!M[v] && flow[f] > 0 ) { |
471 queue.push(v); |
461 queue.push(v); |
472 M.set(v, true); |
462 M.set(v, true); |
473 } |
463 } |
474 } |
464 } |
475 } |
465 } |
483 */ |
473 */ |
484 |
474 |
485 template<typename _CutMap> |
475 template<typename _CutMap> |
486 void maxMinCut(_CutMap& M) { |
476 void maxMinCut(_CutMap& M) { |
487 |
477 |
488 std::queue<NodeIt> queue; |
478 std::queue<Node> queue; |
489 |
479 |
490 M.set(t,true); |
480 M.set(t,true); |
491 queue.push(t); |
481 queue.push(t); |
492 |
482 |
493 while (!queue.empty()) { |
483 while (!queue.empty()) { |
494 NodeIt w=queue.front(); |
484 Node w=queue.front(); |
495 queue.pop(); |
485 queue.pop(); |
496 |
486 |
497 for(InEdgeIt e=G.template first<InEdgeIt>(w) ; e.valid(); ++e) { |
487 |
498 NodeIt v=G.tail(e); |
488 InEdgeIt e; |
499 if (!M.get(v) && flow.get(e) < capacity.get(e) ) { |
489 for(G.first(e,w) ; G.valid(e); G.next(e)) { |
|
490 Node v=G.tail(e); |
|
491 if (!M[v] && flow[e] < capacity[e] ) { |
500 queue.push(v); |
492 queue.push(v); |
501 M.set(v, true); |
493 M.set(v, true); |
502 } |
494 } |
503 } |
495 } |
504 |
496 |
505 for(OutEdgeIt e=G.template first<OutEdgeIt>(w) ; e.valid(); ++e) { |
497 OutEdgeIt f; |
506 NodeIt v=G.head(e); |
498 for(G.first(f,w) ; G.valid(f); G.next(f)) { |
507 if (!M.get(v) && flow.get(e) > 0 ) { |
499 Node v=G.head(f); |
|
500 if (!M[v] && flow[f] > 0 ) { |
508 queue.push(v); |
501 queue.push(v); |
509 M.set(v, true); |
502 M.set(v, true); |
510 } |
503 } |
511 } |
504 } |
512 } |
505 } |
513 |
506 |
514 for(EachNodeIt v=G.template first<EachNodeIt>() ; v.valid(); ++v) { |
507 NodeIt v; |
515 M.set(v, !M.get(v)); |
508 for(G.first(v) ; G.valid(v); G.next(v)) { |
|
509 M.set(v, !M[v]); |
516 } |
510 } |
517 |
511 |
518 } |
512 } |
519 |
513 |
520 |
514 |