ZOJ 3229 有上下界最大流

   1:  /**

   2:      ZOJ 3229 有上下界的最大流

   3:      两次求最大流的过程,非二分

   4:      有源汇上下界的最大流问题, 首先连接 sink -> src, [0,INF].

   5:      根据net的正负,来建立 Supersrc 与 supersink 之间的边,做一次 maxflow.

   6:      若所有的Supersrc 与 Supersink满流,则说明存在可行流.

   7:      然后删除 sink -> src之间的边.(cap 置零即可). 从src -> sink 做一次最大流.

   8:      两次最大流的和即为整个网络的最大流.

   9:  */

  10:   

  11:  #include<iostream>

  12:  #include<cmath>

  13:  #include<memory>

  14:  #include <string.h>

  15:  #include <cstdio>

  16:  #include <vector>

  17:  using namespace std;

  18:   

  19:  #define V 1500      // vertex

  20:  #define E  V *80     // edge

  21:  #define INF 0x3F3F3F3F  // 1061109567

  22:   

  23:  int i,j,k;

  24:  #define REP(i,n) for((i)=0;(i)<(int)(n);(i)++)

  25:  #define snuke(c,itr) for(__typeof((c).begin()) itr=(c).begin();itr!=(c).end();itr++)

  26:   

  27:  struct MaxFlow

  28:  {

  29:      struct Edge

  30:      {

  31:          int v, w, next;     //w for capicity

  32:          int lb,up;

  33:      } edge[E];

  34:   

  35:      int head[V];          // head[u]表示顶点u第一条邻接边的序号, 若head[u] = -1, u没有邻接边

  36:      int e;                // the index of the edge

  37:      int src, sink;

  38:      int net[V];              // 流入此节点的流的下界和 - 流出此节点的流的下界和,对于带上下界的来进行使用

  39:   

  40:   

  41:      void addedge(int  u, int v, int w, int lb = 0, int up = INF, int rw = 0)

  42:      {

  43:          edge[e].v = v;

  44:          edge[e].w= w;

  45:          edge[e].next = head[u];

  46:          edge[e].lb = lb, edge[e].up = up;

  47:          head[u] = e++;

  48:          // reverse edge  v -> u

  49:          edge[e].v = u;

  50:          edge[e].w = rw;

  51:          edge[e].lb = lb, edge[e].up = up;

  52:          edge[e].next = head[v];

  53:          head[v] = e++;

  54:      }

  55:   

  56:      int ISAP(int VertexNum )

  57:      {

  58:          int u, v, max_flow, aug, min_lev;

  59:          int curedge[V], parent[V], level[V];

  60:          int count[V], augment[V];

  61:   

  62:          memset(level, 0, sizeof(level));

  63:          memset(count, 0, sizeof(count));

  64:          REP(i,VertexNum+1) curedge[i] = head[i];

  65:          max_flow = 0;

  66:          augment[src] = INF;

  67:          parent[src] = -1;

  68:          u = src;

  69:   

  70:          while (level[src] < VertexNum)

  71:          {

  72:              if (u == sink)

  73:              {

  74:                  max_flow += augment[sink];

  75:                  aug = augment[sink];

  76:                  for (v = parent[sink]; v != -1; v = parent[v])

  77:                  {

  78:                      i = curedge[v];

  79:                      edge[i].w  -= aug;

  80:                      edge[i^1].w  += aug;

  81:                      augment[edge[i].v] -= aug;

  82:                      if (edge[i].w == 0) u = v;

  83:                  }

  84:              }

  85:              for (i = curedge[u]; i != -1; i = edge[i].next)

  86:              {

  87:                  v = edge[i].v;

  88:                  if (edge[i].w > 0 && level[u] == (level[v]+1))

  89:                  {

  90:                      augment[v] = min(augment[u], edge[i].w);

  91:                      curedge[u] = i;

  92:                      parent[v] = u;

  93:                      u = v;

  94:                      break;

  95:                  }

  96:              }

  97:              if (i == -1)

  98:              {

  99:                  if (--count[level[u]] == 0) break;

 100:                  curedge[u] = head[u];

 101:                  min_lev = VertexNum;

 102:                  for (i = head[u]; i != -1; i = edge[i].next)

 103:                      if (edge[i].w > 0)

 104:                          min_lev = min(level[edge[i].v], min_lev);

 105:                  level[u] = min_lev + 1;

 106:                  count[level[u]]++;

 107:                  if (u != src ) u = parent[u];

 108:              }

 109:          }

 110:          return max_flow;

 111:      }

 112:      // girl 0-m-1, day m,m+n-1, src m+n, sink m+n+1. all m+n+2 point

 113:      void solve()

 114:      {

 115:          int N,M; // n days m girl

 116:          while(scanf("%d%d", &N,&M) != EOF)

 117:          {

 118:              e = 0;

 119:              memset(head, -1, sizeof(head));

 120:              memset(net, 0, sizeof(net));

 121:              int G; src = M+N, sink = M+N+1;

 122:              for(int i=0; i<M; i++)

 123:              {

 124:                  scanf("%d", &G);

 125:                  addedge(i,sink,INF-G, G,INF);

 126:                  net[i] -= G;

 127:                  net[sink] += G;

 128:              }

 129:              vector<int> CE;

 130:              for(int i=0; i<N; i++)

 131:              {

 132:                  int C,D; scanf("%d%d", &C,&D);

 133:                  addedge(src, M+i, D, 0, D);

 134:                  for(int j=0; j<C; j++)

 135:                  {

 136:                      int T,L,R; scanf("%d%d%d", &T,&L,&R);

 137:                      CE.push_back(e);

 138:                      addedge(M+i,T,R-L, L,R);

 139:                      net[M+i] -= L;

 140:                      net[T] += L;

 141:                  }

 142:              }

 143:              int spec = e;

 144:              // 添加从sink -> src 容量为INF的边

 145:              addedge(sink, src, INF,0,INF);

 146:              src = M+N+2; sink = M+N+3;  // M+N+4 point

 147:              int rangea = e;

 148:              for(int i=0; i<M+N+2; i++)

 149:              {

 150:                  if(net[i] >= 0) addedge(src, i, net[i]);

 151:                  else  addedge(i, sink,-net[i]);

 152:              }

 153:              double ret = 0;

 154:              int rangeb = e;

 155:              // 从super src ->super sink 做一次最大流

 156:              ret+=ISAP(M+N+4);

 157:              bool flag = true;

 158:              // 判断是否满流

 159:              for(int i= rangea; i<rangeb; i+=2)

 160:              {

 161:                  if(edge[i].w !=0)

 162:                  {

 163:                      flag = false;

 164:                      break;

 165:                  }

 166:              }

 167:              if(flag)

 168:              {

 169:                  // 修改 src sink,然后把 从sink -> src 的边删除

 170:                  src = M+N; sink = M+N+1;

 171:                  edge[spec].w = 0; edge[spec+1].w = 0;

 172:                  // 从 src->sink 做一次最大流

 173:                  ret += ISAP(M+N+2);

 174:                  int tmp = ret;

 175:                  printf("%d\n", tmp);

 176:                  for(int i=0; i<CE.size(); i++)

 177:                      printf("%d\n", edge[CE[i]+1].lb + edge[CE[i]+1].w);

 178:              }else printf("-1\n");

 179:              cout<<endl;

 180:          }

 181:      }

 182:  }sap;

 183:   

 184:  int main()

 185:  {

 186:  //    freopen("1.txt","r",stdin);

 187:      sap.solve();

 188:      return 0;

 189:  }

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