POJ 1459(EK)

这题是学着小媛学姐写的..

 1 #include<cstdio>

 2 #include<cstring>

 3 #include<iostream>

 4 #include<queue>

 5 #include <climits>

 6 using namespace std;

 7 #define N 120

 8 

 9 int n, np, nc, m;

10 int cap[N][N];

11 int EK(int s, int t)

12 {

13     queue<int> q;

14     int flow[N][N];

15     int low[N];

16     int u,v,maxflow=0;

17     int pre[N];

18     memset(flow,0,sizeof(flow));

19     while(1)

20     {

21         q.push(s);

22         memset(low,0,sizeof(low));

23         low[s] = INT_MAX;

24         while(!q.empty())

25         {

26             u = q.front();

27             q.pop();

28             for(v = 0; v <= t; v ++)

29             {

30                 if(!low[v] && cap[u][v] > flow[u][v])

31                 {

32                     q.push(v);

33                     low[v] = min(low[u], cap[u][v] - flow[u][v]);

34                     pre[v] = u;

35                 }

36             }

37         }

38         if(low[t] == 0) break;

39         for(u = t; u != s; u = pre[u])

40         {

41             flow[pre[u]][u] += low[t];

42             flow[u][pre[u]] -= low[t];

43         }

44         maxflow += low[t];

45     }

46     return maxflow;

47 }

48 int main()

49 {

50     char ch;

51     int from, to, len, ans;

52     while(~scanf("%d%d%d%d",&n,&np,&nc,&m))

53     {

54         memset(cap, 0, sizeof(cap));

55         while(m--)

56         {

57             scanf(" (%d,%d)%d", &from, &to, &len);

58             cap[from][to] = len;

59         }

60         while(np--)

61         {

62             scanf(" (%d)%d",&from, &len);

63             cap[n+1][from] = len;

64         }

65         while(nc--)

66         {

67             scanf(" (%d)%d",&from, &len);

68             cap[from][n+2] = len;

69         }

70         ans = EK(n+1, n+2);

71         printf("%d\n",ans);

72     }

73     return 0;

74 }

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