Pagini recente » Cod sursa (job #2377652) | Cod sursa (job #2543497) | Cod sursa (job #120666) | Cod sursa (job #1787303) | Cod sursa (job #1110997)
#include <fstream>
#include <iostream>
#include <vector>
#include <bitset>
#include <string.h>
#include <algorithm>
#include <iomanip>
#include <math.h>
#include <time.h>
#include <stdlib.h>
#include <set>
#include <map>
#include <string>
#include <queue>
#include <deque>
#include <cassert>
using namespace std;
const char infile[] = "maxflow.in";
const char outfile[] = "maxflow.out";
ifstream fin(infile);
ofstream fout(outfile);
const int MAXN = 1005;
const int oo = 0x3f3f3f3f;
typedef vector<int> Graph[MAXN];
typedef vector<int> :: iterator It;
const inline int min(const int &a, const int &b) { if( a > b ) return b; return a; }
const inline int max(const int &a, const int &b) { if( a < b ) return b; return a; }
const inline void Get_min(int &a, const int b) { if( a > b ) a = b; }
const inline void Get_max(int &a, const int b) { if( a < b ) a = b; }
int N, M;
Graph G;
int Qu[MAXN][MAXN];
int F[MAXN][MAXN];
bitset <MAXN> Used;
int Father[MAXN];
inline bool BFs(const int &Source, const int &Sink) {
queue <int> Q;
Used.reset();
Q.push(Source);
Used[Source] = true;
while(!Q.empty()) {
int Node = Q.front();
Q.pop();
for(It it = G[Node].begin(), fin = G[Node].end(); it != fin ; ++ it)
if(!Used[*it] && Qu[Node][*it] - F[Node][*it] > 0) {
Used[*it] = true;
Father[*it] = Node;
Q.push(*it);
}
}
return Used[Sink];
}
int main() {
fin >> N >> M;
for(int i = 1 ; i <= M ; ++ i) {
int x, y, z;
fin >> x >> y >> z;
Qu[x][y] = z;
G[x].push_back(y);
G[y].push_back(x);
}
int maxFlow = 0;
int Source = 1, Sink = N;
while(BFs(Source, Sink)) {
for(It it = G[Sink].begin(), fin = G[Sink].end(); it != fin ; ++ it) {
if(!Used[*it] || Qu[*it][Sink] - F[*it][Sink] <= 0)
continue;
Father[Sink] = *it;
int bottleNeck = oo; /// We keep learning
for(int i = Sink ; i != Source ; i = Father[i])
bottleNeck = min(bottleNeck, Qu[Father[i]][i] - F[Father[i]][i]);
assert(bottleNeck != 0);
for(int i = Sink ; i != Source ; i = Father[i]) {
F[Father[i]][i] += bottleNeck;
F[i][Father[i]] -= bottleNeck;
}
maxFlow += bottleNeck;
}
}
fout << maxFlow << '\n';
fin.close();
fout.close();
return 0;
}