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| #include <bits/stdc++.h>
#pragma optimization_level 3
#pragma GCC optimize("Ofast,no-stack-protector,unroll-loops,fast-math,O3")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx")
#pragma GCC optimize("Ofast")
#pragma GCC target("avx,avx2,fma")
#pragma GCC optimization ("unroll-loops")
#define MAX_N 444
#define INF 987654321987654321
#define ll long long
#define pll pair<ll, ll>
#define vpll vector<pll>
#define vall3 vector<array<ll,3>>
#define all5 array<ll,5>
#define vall5 vector<all5>
#define vll vector<ll>
#define vs vector<string>
#define usll unordered_set<ll>
#define vvs vector<vs>
#define vvll vector<vll>
#define all(a) begin(a), end(a)
using namespace std;
ll source = 404, sink = 405;
ll cap[MAX_N][MAX_N], cost[MAX_N][MAX_N], flo[MAX_N][MAX_N], path[MAX_N];
vll adj[MAX_N];
void connect(ll u, ll v, ll capacity, ll weight) {
adj[u].push_back(v);
adj[v].push_back(u);
cap[u][v] += capacity;
cost[u][v] += weight;
cost[v][u] += -weight;
}
bool bfs(ll u, ll v) {
vll w(MAX_N, INF);
bool inc[MAX_N];
memset(path, 0, sizeof path);
memset(inc, 0, sizeof inc);
queue<ll> q;
q.push(u);
w[u] = 0;
while(!q.empty()) {
auto n = q.front(); q.pop();
inc[n] = false;
for(auto& m : adj[n]) {
if(cap[n][m] - flo[n][m] > 0 and w[n] + cost[n][m] < w[m]) {
w[m] = w[n] + cost[n][m];
path[m] = n;
if(!inc[m]) {
inc[m] = true;
q.push(m);
}
}
}
}
return path[v] != 0;
}
pll solve() {
ll res = 0, flow = 0;
while(bfs(source, sink)) {
ll v = sink, mi = INF;
while(source != v) {
ll u = path[v];
mi = min(mi, cap[u][v] - flo[u][v]);
v = u;
}
v = sink;
flow += mi;
while(source != v) {
ll u = path[v];
res += mi * cost[u][v];
flo[u][v] += mi;
flo[v][u] -= mi;
v = u;
}
}
return {flow, res};
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.setf(ios::fixed);
cout.precision(6);
ll n, m, u, v, w;
cin>>n>>m;
for(ll i = 1, gap = 200; i <= m; i++) {
cin>>u>>v>>w;
connect(u,v + gap,1,w);
}
for(ll i = 1, gap = 200; i <= n; i++) {
connect(source, i, 1, 0);
connect(i + gap, sink, 1, 0);
}
auto [flow, res] = solve();
cout<<(flow == n)<<'\n';
if(flow != n) exit(0);
cout<<res<<'\n';
for(ll u = 1; u <= n; u++) {
for(auto& v : adj[u]) {
if(flo[u][v] and v != source and v != sink) {
cout << u << ' ' << v - 200 << '\n';
}
}
}
return 0;
}
|
