二分图匹配

using namespace std;

const LL MAXN = 9000001;

struct N
{
    unsigned int v,next;
}edge[MAXN*2];

int head[MAXN];

int Top;

void Link(unsigned int u,unsigned int v)
{
    edge[Top].v = v;

    edge[Top].next = head[u];
    head[u] = Top++;
}

void Init_head_Top(int n)
{
    memset(head,-1,sizeof(unsigned int)*(n+2));
    Top = 0;
}

int Match_Point[MAXN];

bool mark[MAXN];

bool dfs(int s)
{
    for(int p = head[s] ; p != -1; p = edge[p].next)
    {
        if(mark[edge[p].v] == false)
        {
            mark[edge[p].v] = true;
            if(Match_Point[edge[p].v] == -1 || dfs(Match_Point[edge[p].v]))
            {
                Match_Point[s] = edge[p].v;
                Match_Point[edge[p].v] = s;
                return true;
            }
        }
    }
    return false;
}

int Cal_Max_Match(int n)
{
    int ans = 0;

    for(int i = 1;i <= n; ++i)
    {
        if(Match_Point[i] == -1)
        {
            memset(mark,false,sizeof(bool)*(n+2));
            if(dfs(i))
                ans++;
        }
    }
    return ans;
}