Edmond_Karp算法

核心思想:通过bfs不断在网络中寻找最短的增广路,从而求得最大流.
时间复杂度O(VE^2)

算法模板:

int Edmond_Karp(int s,int t)

{

    int ans=0;

    memset(flow,0,sizeof(flow));

    while (1)

    {

        memset(a,0,sizeof(a));

        memset(p,0,sizeof(p));

        a[s]=INF;

        q.push(s);

        while (!q.empty())

        {

            int u=q.front();

            q.pop();

            for (int v=1;v<=n;v++)

            if (!a[v] && map[u][v]>flow[u][v])

            {

                p[v]=u;

                q.push(v);

                a[v]=Min(a[u],map[u][v]-flow[u][v]);

            }

        }

        if (a[t]==0) break;

        for (int u=t;u!=s;u=p[u])

        {

            flow[p[u]][u]+=a[t];

            flow[u][p[u]]-=a[t];

        }

        ans+=a[t];

    }

    return ans;

}