Cod sursa(job #1396972)

Utilizator robertstrecheStreche Robert robertstreche Data 23 martie 2015 10:33:44
Problema Flux maxim Scor 70
Compilator cpp Status done
Runda Arhiva educationala Marime 1.3 kb
#include <cstdio>
#include <vector>
#include <bitset>
#include <stack>
#include <cstring>

#define NMAX 1005
#define INF 0x3f3f3f3f

using namespace std;

stack <int>s;
bitset <NMAX>ap;
vector <int>v[NMAX];

int n,m,x,y,z,flow;
int boss[NMAX],cap[NMAX][NMAX];

inline bool df()
{
    for (;!s.empty();s.pop());
    s.push(1);
    while (!s.empty())
    {
       int nod=s.top();
       s.pop();
       for (auto it:v[nod])
        if (!ap[it] && cap[nod][it])
        {
          ap[it]=1;
          boss[it]=nod;
          if (it==n)return 1;
          s.push(it);
        }
    }
   return 0;
}
int main()
{
    freopen("maxflow.in","r",stdin);
    freopen("maxflow.out","w",stdout);

    scanf ("%d %d",&n,&m);

    for (;m;m--)
    {
        scanf("%d %d %d",&x,&y,&z);

        v[x].push_back(y);
        v[y].push_back(x);
        cap[x][y]+=z;
    }
    ap[1]=1;
    while (df())
    {
        int maxflow=INF;
        for (int i=n;i!=1;i=boss[i])
          maxflow=(maxflow>cap[boss[i]][i]?cap[boss[i]][i]:maxflow);
        for (int i=n;i!=1;i=boss[i])
          cap[boss[i]][i]-=maxflow,
          cap[i][boss[i]]+=maxflow;
        flow+=maxflow;
        for (int i=2;i<=n;i++)ap[i]=0;
    }
    printf("%d",flow);

    fclose(stdin);
    fclose(stdout);
}