poj 3680(最大费用最大流)

构图参考：http://www.cppblog.com/abilitytao/archive/2010/03/30/111042.html

  1 // File Name: 3680.cpp

  2 // Author: Missa

  3 // Created Time: 2013/4/19 星期五 15:57:48

  4 

  5 #include<iostream>

  6 #include<cstdio>

  7 #include<cstring>

  8 #include<algorithm>

  9 #include<cmath>

 10 #include<queue>

 11 #include<stack>

 12 #include<string>

 13 #include<vector>

 14 #include<cstdlib>

 15 #include<map>

 16 #include<set>

 17 using namespace std;

 18 #define CL(x,v) memset(x,v,sizeof(x));

 19 #define R(i,st,en) for(int i=st;i<en;++i)

 20 #define LL long long

 21 

 22 const int maxn = 450;

 23 const int maxm = 450 * 450;

 24 const int inf = 0x3f3f3f3f;

 25 struct Edge

 26 {

 27     int v, cap, cost, next;

 28 }p[maxm << 1];

 29 int e, sumFlow, n, m, st, en;

 30 int head[maxn], dis[maxn], pre[maxn];

 31 bool vis[maxn];

 32 void init()

 33 {

 34     e=0;

 35     memset(head,-1,sizeof(head));

 36 }

 37 void addEdge(int u,int v,int cap,int cost)

 38 {

 39     p[e].v = v; p[e].cap = cap; p[e].cost = cost;

 40     p[e].next = head[u]; head[u] = e++;

 41     p[e].v = u; p[e].cap = 0; p[e].cost = - cost;

 42     p[e].next = head[v]; head[v] = e++;

 43 }

 44 bool spfa(int s,int t, int n)

 45 {

 46     int u,v;

 47     queue<int>q;

 48     memset(vis,false,sizeof(vis));

 49     memset(pre,-1,sizeof(pre));

 50     for(int i = 0; i <= n; ++i) 

 51         dis[i] = inf;

 52     vis[s] = true;

 53     dis[s] = 0;

 54     q.push(s);

 55     while(!q.empty())

 56     {

 57         u = q.front();

 58         q.pop();

 59         vis[u] = false;

 60         for(int i = head[u]; i != -1; i = p[i].next)

 61         {

 62             v = p[i].v;

 63             if(p[i].cap && dis[v] > dis[u] + p[i].cost)

 64             {

 65                 dis[v] = dis[u] + p[i].cost;

 66                 pre[v] = i;

 67                 if(!vis[v])

 68                 {

 69                     q.push(v);

 70                     vis[v]=true;

 71                 }

 72             }

 73         }

 74      }

 75      if(dis[t] == inf) 

 76          return false;

 77      return true;

 78 }

 79 int MCMF(int s,int t,int n)

 80 {

 81     int flow = 0; // 总流量

 82     int minflow, mincost;

 83     mincost=0;

 84     while(spfa(s,t,n))

 85     {

 86         minflow = inf + 1;

 87         for(int i = pre[t]; i != -1; i = pre[p[i^1].v])

 88             if(p[i].cap < minflow)

 89                 minflow = p[i].cap;

 90         flow += minflow;

 91         for(int i=pre[t];i!=-1;i=pre[p[i^1].v])

 92         {

 93             p[i].cap -= minflow;

 94             p[i^1].cap += minflow;

 95         }

 96         mincost += dis[t] * minflow;

 97     }

 98     sumFlow = flow; // 最大流

 99     return mincost;

100 }

101 int N, K;

102 struct Node

103 {

104     int u, v, c;

105 }ed[maxn];

106 int pos[100005];

107 vector<int>v;

108 int main()

109 {

110     int test;

111     scanf("%d",&test);

112     while (test--)

113     {

114         init();

115         n = 1;

116         memset(pos, 0, sizeof(pos));

117         scanf("%d%d", &N, &K);

118         v.clear();

119         for (int i = 0; i < N; ++i)

120         {

121             scanf("%d%d%d",&ed[i].u, &ed[i].v, &ed[i].c);

122             v.push_back(ed[i].u);

123             v.push_back(ed[i].v);

124         }

125         sort(v.begin(),v.end());

126         for (int i = 0; i < v.size(); ++i)

127             if (pos[v[i]] == 0)

128                 pos[v[i]] = n ++;

129         st = 0, en = n;

130         for (int i = 0; i < n; ++i)

131             addEdge(i, i + 1, K, 0);

132         for (int i = 0; i < N; ++i)

133             addEdge(pos[ed[i].u], pos[ed[i].v], 1, -ed[i].c);

134         printf("%d\n",-MCMF(st, en, n));

135     }

136     return 0;

137 }