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| #include <bits/stdc++.h>
using namespace std;
typedef long long LL;
template <typename Int>
void getInt(Int &x) {
x = 0; char ch = getchar(); Int sgn = 1;
while (!isdigit(ch)) { if (ch == '-') sgn = -1; ch = getchar(); }
while (isdigit(ch)) { x = (x << 3) + (x << 1) + (ch ^ 48); ch = getchar(); }
x *= sgn;
}
namespace NetworkFlow {
const LL maxn = 10000 * 4 + 100;
LL n, m, s, t, tot;
struct Edge {
LL from, to, cap, flow;
Edge(LL from_ = 0, LL to_ = 0, LL cap_ = 0, LL flow_ = 0)
: from(from_), to(to_), cap(cap_), flow(flow_) {}
};
vector <Edge> edges;
vector <LL> g[maxn];
void addEdge(LL from, LL to, LL cap) {
edges.push_back(Edge(from, to, cap, 0));
edges.push_back(Edge(to, from, 0, 0));
tot = edges.size();
g[from].push_back(tot - 2);
g[to].push_back(tot - 1);
}
bool vis[maxn];
LL d[maxn], cur[maxn];
queue <LL> q;
bool bfs() {
memset(vis, 0, sizeof vis);
while (!q.empty()) q.pop();
q.push(s); d[s] = 0; vis[s] = 1;
while (!q.empty()) {
LL x = q.front(); q.pop();
for (unsigned i = 0; i < g[x].size(); ++i) {
Edge &e = edges[g[x][i]];
if (!vis[e.to] && e.cap > e.flow) {
vis[e.to] = 1;
d[e.to] = d[x] + 1;
q.push(e.to);
}
}
}
return vis[t];
}
LL dfs(LL x, LL a) {
if (x == t || a == 0) return a;
LL flow = 0, f;
for (LL &i = cur[x]; i < g[x].size(); ++i) {
Edge &e = edges[g[x][i]];
if (d[x] + 1 == d[e.to] && (f = dfs(e.to, min(a, e.cap - e.flow))) > 0) {
e.flow += f; edges[g[x][i] ^ 1].flow -= f;
flow += f; a -= f;
if (!a) break;
}
}
return flow;
}
LL maxFlow() {
LL flow = 0;
while (bfs()) {
memset(cur, 0, sizeof cur);
flow += dfs(s, INT_MAX);
}
return flow;
}
void init() {
edges.clear();
for (LL i = 0; i < maxn; ++i) g[i].clear();
memset(vis, 0, sizeof vis);
memset(d, 0, sizeof d);
memset(cur, 0, sizeof cur);
while (!q.empty()) q.pop();
n = m = s = t = tot = 0;
}
};
const LL MAX_N = 10000 + 5;
LL T, n, m;
struct Edge {
LL from, to, cost;
Edge(LL from_ = 0, LL to_ = 0, LL cost_ = 0)
: from(from_), to(to_), cost(cost_) {}
};
vector <Edge> g[MAX_N];
vector <Edge> edgeVec;
LL d[MAX_N];
void ssspInit() {
for (LL i = 0; i <= n; ++i) {
g[i].clear();
}
edgeVec.clear();
}
struct Status {
LL val, to;
Status(LL val_ = 0, LL to_ = 0)
: val(val_), to(to_) {}
friend bool operator > (const Status &sx, const Status &sy) {
return sx.val > sy.val;
}
};
priority_queue < Status, vector <Status>, greater <Status> > q;
LL dijkstra() {
while (!q.empty()) q.pop();
for (LL i = 1; i <= n; ++i) d[i] = LL(1E18);
d[1] = 0; q.push(Status(0, 1));
while (!q.empty()) {
Status f = q.top(); q.pop();
for (unsigned i = 0; i < g[f.to].size(); ++i) {
Edge &e = g[f.to][i];
if (f.val + e.cost < d[e.to]) {
d[e.to] = f.val + e.cost;
q.push(Status(d[e.to], e.to));
}
}
}
return d[n];
}
int main() {
scanf("%lld", &T);
for (LL cs = 1; cs <= T; ++cs) {
scanf("%lld%lld", &n, &m);
LL u, v, c;
ssspInit();
for (LL i = 1; i <= m; ++i) {
scanf("%lld%lld%lld", &u, &v, &c);
g[u].push_back(Edge(u, v, c));
edgeVec.push_back(Edge(u, v, c));
}
LL sssp = dijkstra();
if (sssp == LL(1E18)) {
puts("0");
continue;
}
NetworkFlow::init();
for (auto const &e: edgeVec) {
if (d[e.from] + e.cost == d[e.to]) {
NetworkFlow::addEdge(e.from, e.to, e.cost);
}
}
NetworkFlow::s = 1; NetworkFlow::t = n;
LL ans = NetworkFlow::maxFlow();
printf("%lld\n", ans);
}
return 0;
}
|