Pagini recente » Cod sursa (job #522276) | Cod sursa (job #1960212) | Cod sursa (job #2410343) | Cod sursa (job #2258810) | Cod sursa (job #2985288)
#include <fstream>
#include <iostream>
#include <queue>
#include <cstring>
using namespace std;
ifstream fin("maxflow.in");
ofstream fout("maxflow.out");
const int MAX_N = 1005;
const int INF = 0x3f3f3f3f;
int n, m;
int graph[MAX_N][MAX_N];
int flow[MAX_N][MAX_N];
int father[MAX_N];
queue <int> q;
void InitQueue() {
while (!q.empty()) {
q.pop();
}
q.push(1);
}
bool BFS() {
InitQueue();
memset(father, 0, sizeof(father));
father[1] = 1;
while (!q.empty()) {
int node = q.back();
q.pop();
if (node == n) {
return true;
}
for (int i = 1; i <= n; i++) {
if (!father[i] && graph[node][i] - flow[node][i] > 0) {
q.push(i);
father[i] = node;
}
}
}
}
int GetMin() {
int minVal = INF;
int node = n;
while (father[node] != node) {
int parent = father[node];
if (flow[parent][node] < minVal) {
minVal = graph[parent][node] - flow[parent][node];
}
node = parent;
}
return minVal;
}
void UpdateFlow(int value) {
int node = n;
while (father[node] != node) {
int parent = father[node];
flow[parent][node] += value;
flow[node][parent] -= value;
node = parent;
}
}
int main() {
fin >> n >> m;
for (int i = 0; i < m; i++) {
int a, b, c;
fin >> a >> b >> c;
graph[a][b] = c;
graph[b][a] = c;
flow[b][a] = c;
}
while (BFS()) {
int minVal = GetMin();
UpdateFlow(minVal);
}
int ans = 0;
for (int i = 1; i <= n; i++) {
ans += flow[1][i];
}
fout << ans << '\n';
return 0;
}