题目链接：http://acm.hdu.edu.cn/showproblem.php?pid=3549

思路分析：该问题为裸的最大网络流问题，数据量不大，使用EdmondsKarp算法求解即可；需要注意的是该问题的点最多有15个，边的数目最多有1000个，所以该图中存在重边，需要将多个重边合为一条边；

代码如下：

#include 
#include 
#include 
#include 
#include 
#include 
using namespace std;const int MAX_N = 20;
int cap[MAX_N][MAX_N], flow[MAX_N][MAX_N];
int a[MAX_N], p[MAX_N];inline int Min(int a, int b) { return a < b ? a : b; }
int EdmondsKarp(int ver_num)
{queue q;int max_flow = 0;memset(flow, 0, sizeof(flow));for (;;){memset(a, 0, sizeof(a));a[1] = INT_MAX;q.push(1);while (!q.empty()){int u = q.front();q.pop();for (int v = 1; v <= ver_num; ++v){if (!a[v] && cap[u][v] > flow[u][v]){p[v] = u;q.push(v);a[v] = Min(a[u], cap[u][v] - flow[u][v]);}}}if (a[ver_num] == 0)  break;for (int u = ver_num; u != 1; u = p[u]){flow[p[u]][u] += a[ver_num];flow[u][p[u]] -= a[ver_num];}max_flow += a[ver_num];}return max_flow;
}int main()
{int case_times, case_id = 0;int road_num, ver_num;scanf("%d", &case_times);while (case_times--){int ver_1, ver_2, capa;scanf("%d %d", &ver_num, &road_num);memset(cap, 0, sizeof(cap));for (int i = 0; i < road_num; ++i){scanf("%d %d %d", &ver_1, &ver_2, &capa);cap[ver_1][ver_2] += capa;}int ans = EdmondsKarp(ver_num);printf("Case %d: %d\n", ++case_id, ans);}return 0;
}