Cod sursa(job #989772)
#include <algorithm>
#include <fstream>
#include <iostream>
#include <queue>
#include <vector>
using namespace std;
ifstream fin("maxflow.in");
ofstream fout("maxflow.out");
const int MAX_N = 1005;
const int INF = 1 << 30;
int N, M;
vector<int> graph[MAX_N];
int residual_capacity[MAX_N][MAX_N];
int incoming[MAX_N];
int dist[MAX_N];
int source, sink;
void read_input();
int maxflow();
bool find_augmenting_path();
int main() {
read_input();
fout << maxflow();
}
void read_input() {
fin >> N >> M;
for (int i = 1, a, b, c; i <= M; ++i) {
fin >> a >> b >> c;
graph[a].push_back(b);
graph[b].push_back(a);
residual_capacity[a][b] = c;
}
source = 1;
sink = N;
}
int maxflow() {
int result = 0;
while (find_augmenting_path()) {
int flow = INF;
for (int node = sink; node != source; node = incoming[node]) {
flow = min(flow, residual_capacity[incoming[node]][node]);
}
result += flow;
for (int node = sink; node != source; node = incoming[node]) {
residual_capacity[incoming[node]][node] -= flow;
residual_capacity[node][incoming[node]] += flow;
}
}
return result;
}
bool find_augmenting_path() {
fill(dist + 1, dist + N + 1, INF);
queue<int> q;
q.push(source);
dist[source] = 0;
while (!q.empty()) {
int node = q.front();
q.pop();
for (auto next : graph[node]) {
if (residual_capacity[node][next] > 0) {
if (dist[node] + 1 < dist[next]) {
dist[next] = dist[node] + 1;
incoming[next] = node;
q.push(next);
if (next == sink) return true;
}
}
}
}
return false;
}