POJ 1459 Power Network Multi-source multi-stream networks

Title Link: http://poj.org/problem?id=1459

Test instructions

A total of n points, M edge, there is a NP point is a gas station is the source point, there are NC points is a point of consumption, that is, meeting point.

Gives the capacity of the M-bar, the maximum outflow per source point, and the maximum inflow per sink point.

Can consume as much as you please.

Ideas:

A multi-source multi-sink network stream is the addition of a super-source point and a super-sink point.

An edge is attached to each source point by the source point, and the capacity is the maximum amount of the source point outflow.

Connect each meeting point to a super meeting point with a capacity of the maximum inflow specified for that meeting point.

Then the maximum flow is calculated.

1 //#include <bits/stdc++.h>2#include <iostream>3#include <cstring>4#include <cstdio>5#include <vector>6#include <queue>7 using namespacestd;8 intN, m, S, T;9 #defineMAXN 110Ten #defineINF 0x3f3f3f3f One structEdge A { -     int  from, to, cap, flow; -Edge (intFintTintCintFL) the     { -          from= f; to = t; Cap = C; Flow =FL; -     } - }; +Vector <Edge>edges; -Vector <int>G[MAXN]; + intD[MAXN], VIS[MAXN], CUR[MAXN]; A voidAddedge (int  from,intTo,intcap) at { -Edges.push_back (Edge ( from, to, Cap,0)); -Edges.push_back (Edge to, from,0,0)); -m =edges.size (); -g[ from].push_back (M-2); -G[to].push_back (M-1); in } - BOOLBFS () to { +memset (Vis,0,sizeof(Vis)); -D[s] =0; theVis[s] =1; *Queue <int>Q; $ Q.push (s);Panax Notoginseng      while(!q.empty ()) -     { the         intx =Q.front (); Q.pop (); +          for(inti =0; I < g[x].size (); i++) A         { theEdge &e =Edges[g[x][i]]; +             if(!vis[e.to] && e.cap >E.flow) -             { $D[e.to] = D[x] +1; $Vis[e.to] =1; - Q.push (e.to); -             } the         } -     }Wuyi     returnVis[t]; the } - intDfsintXinta) Wu { -     if(x = = T | | a = =0)returnA; About     intFlow =0, F; $      for(int&i = Cur[x]; I < g[x].size (); i++) -     { -Edge &e =Edges[g[x][i]]; -         if(d[e.to] = = D[x] +1&& (f = dfs (e.to, Min (A, e.cap-e.flow))) >0) A         { +E.flow + =F; theedges[g[x][i]^1].flow-=F; -Flow + =F; $A-=F; the             if(A = =0) Break; the         } the     } the     returnflow; - } in intMaxflow () the { the     intFlow =0; About      while(BFS ()) the     { thememset (cur,0,sizeof(cur)); theFlow + =DFS (s, INF); +     } -     returnflow; the }Bayi intN, NP, NC, M; the intMain () the { -     //freopen ("In.txt", "R", stdin); -     //freopen ("OUT.txt", "w", stdout); the      while(~SCANF ("%d%d%d%d", &n, &AMP;NP, &AMP;NC, &M)) the     { the edges.clear (); the          for(inti =0; I <= n+1; i++) g[i].clear (); -         intA, B, C;Charop; the          for(inti =1; I <= M; i++) the         { thecin>>op; scanf"%d", &a); 94cin>>op; scanf"%d", &b); thecin>>op; scanf"%d", &c); the Addedge (A, B, c); the         }98s = N; t = n+1; About          for(inti =1; I <= NP; i++) -         {101cin>>op; scanf"%d", &a);102cin>>op; scanf"%d", &c);103 Addedge (S, a, c);104         } the          for(inti =1; I <= NC; i++)106         {107cin>>op; scanf"%d", &a);108cin>>op; scanf"%d", &c);109 Addedge (A, t, c); the         }111n = n+2; the         intFlow =Maxflow ();113printf"%d\n", flow); the     } the     return 0; the}

POJ 1459 Power Network Multi-source multi-stream networks