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| #include <iostream>
#include <queue>
#include <cstdio>
#define MAXN 1010
#define INF 0x3f3f3f3f
using namespace std;
struct Node;
struct Edge;
int n,m;
struct Node
{
Edge *firstEdge, *currentEdge;
int level;
Node()
{
firstEdge = NULL;
}
}node[MAXN];
struct Edge
{
Node *from, *to;
int capacity, flow;
Edge *next, *reverseEdge;
Edge(Node *from, Node *to, int capacity):from(from),to(to),capacity(capacity),flow(0),next(from->firstEdge) {}
~Edge()
{
delete next;
}
};
struct Dinic
{
bool makeLevelGraph(Node *s, Node *t, int n)
{
for (int i = 1; i<=n; i++)
{
node[i].level = 0;
node[i].currentEdge = node[i].firstEdge;
}
queue<Node *> q;
q.push(s);
s->level = 1;
while (!q.empty())
{
Node *v = q.front();
q.pop();
for (Edge *e = v->firstEdge; e; e = e->next)
if (e->flow<e->capacity && e->to->level==0)
{
e->to->level = v->level + 1;
if (e->to==t)
return true;
else q.push(e->to);
}
}
return false;
}
int findPath(Node *s, Node *t, int limit = INF)
{
if (s==t)
return limit;
for (Edge *&e = s->currentEdge; e; e = e->next)
if (e->to->level==s->level+1 && e->flow < e->capacity)
{
int flow = findPath(e->to, t, min(limit, e->capacity - e->flow));
if (flow>0)
{
e->flow += flow;
e->reverseEdge->flow -= flow;
return flow;
}
}
return 0;
}
int operator()(int s, int t, int n)
{
int ans = 0;
while (makeLevelGraph(&node[s], &node[t], n))
{
int flow;
while ((flow = findPath(&node[s], &node[t]))>0 )
ans += flow;
}
return ans;
}
}dinic;
int main()
{
ios::sync_with_stdio(false);
int T;
scanf("%d",&T);
while (T--)
{
int s,t;
scanf("%d%d%d%d",&n,&m,&s,&t);
for (int i = 1; i<=n; i++)
{
delete node[i].firstEdge;
node[i] = Node();
}
for (int i = 1; i<=m; i++)
{
int x,y,z;
scanf("%d%d%d",&x,&y,&z);
node[x].firstEdge = new Edge(&node[x], &node[y], z*(1+m)+1);
node[y].firstEdge = new Edge(&node[y], &node[x], 0);
node[x].firstEdge->reverseEdge = node[y].firstEdge;
node[y].firstEdge->reverseEdge = node[x].firstEdge;
}
int ans = dinic(s, t, n);
cout << ans%(1+m) << endl;
}
}
|