1 #include <iostream>
 2 #include <queue>
 3 #include<string.h>
 4 using namespace std;
 5 #define arraysize 201
 6 int maxData = 0x7fffffff;
 7 int capacity[arraysize][arraysize]; //记录残留网络的容量
 8 int flow[arraysize];                //标记从源点到当前节点实际还剩多少流量可用
 9 int pre[arraysize];                 //标记在这条路径上当前节点的前驱,同时标记该节点是否在队列中
10 int n,m;
11 queue<int> myqueue;
12 int BFS(int src,int des)
13 {
14     int i,j;
15     while(!myqueue.empty())       //队列清空
16         myqueue.pop();
17     for(i=1;i<m+1;++i)
18     {
19         pre[i]=-1;
20     }
21     pre[src]=0;
22     flow[src]= maxData;
23     myqueue.push(src);
24     while(!myqueue.empty())
25     {
26         int index = myqueue.front();
27         myqueue.pop();
28         if(index == des)            //找到了增广路径
29             break;
30         for(i=1;i<m+1;++i)
31         {
32             if(i!=src && capacity[index][i]>0 && pre[i]==-1)
33             {
34                  pre[i] = index; //记录前驱
35                  flow[i] = min(capacity[index][i],flow[index]);   //关键：迭代的找到增量
36                  myqueue.push(i);
37             }
38         }
39     }
40     if(pre[des]==-1)      //残留图中不再存在增广路径
41         return -1;
42     else
43         return flow[des];
44 }
45 int maxFlow(int src,int des)
46 {
47     int increasement= 0;
48     int sumflow = 0;
49     while((increasement=BFS(src,des))!=-1)
50     {
51          int k = des;          //利用前驱寻找路径
52          while(k!=src)
53          {
54               int last = pre[k];
55               capacity[last][k] -= increasement; //改变正向边的容量
56               capacity[k][last] += increasement; //改变反向边的容量
57               k = last;
58          }
59          sumflow += increasement;
60     }
61     return sumflow;
62 }
63 int main()
64 {
65     int i,j;
66     int start,end,ci;
67     while(cin>>n>>m)
68     {
69         memset(capacity,0,sizeof(capacity));
70         memset(flow,0,sizeof(flow));
71         for(i=0;i<n;++i)
72         {
73             cin>>start>>end>>ci;
74             if(start == end)               //考虑起点终点相同的情况
75                continue;
76             capacity[start][end] +=ci;     //此处注意可能出现多条同一起点终点的情况
77         }
78         cout<<maxFlow(1,m)<<endl;
79     }
80     return 0;
81 }