二分图匹配模板（dfs+bfs）

dfs版：

bool dfs(int u)
{
    for(int i = head[u]; ~i; i = e[i].next) {
        int v = e[i].v;
        if(!vis[v]) {
            vis[v] = true;
            if(my[v] == -1 || dfs(my[v])) {
                my[v] = u;
                mx[u] = v;
                return true;
            }
        }
    }
    return false;
}

int hungary()
{
    int ret = 0;
    memset(mx, -1, sizeof(mx));
    memset(my, -1, sizeof(my));
    for(int i = 1; i <= X; i++) {
        if(mx[i] == -1) {
            memset(vis, 0, sizeof(vis));
            if(dfs(i)) ret++;
        }
    }
    return ret;
}

bfs版：

bool bfs(int st)
{
    queue <int> q;
    q.push(st);
    pre[st] = -1;
    bool flag = false;
    while(!q.empty() && !flag) {
        int u = q.front(); q.pop();
        for(int i = head[u]; ~i && !flag; i = e[i].next) {
            int v = e[i].v;
            if(vis[v] != st) {
                vis[v] = st;
                q.push(my[v]);
                if(~my[v]) pre[my[v]] = u;
                else {
                    int a = u, b = v;
                    flag = true;
                    while(~a) {
                        int t = mx[a];
                        mx[a] = b;
                        my[b] = a;
                        a = pre[a];
                        b = t;
                    }
                }
            }
        }
    }
    return mx[st] != -1;
}

int hungary()
{
    int ret = 0;
    memset(mx, -1, sizeof(mx));
    memset(my, -1, sizeof(my));
    memset(vis, -1, sizeof(vis));
    for(int i = 1; i <= nX; i++) {//number from 1
        if(mx[i] == -1) {
            if(bfs(i)) ret++;
        }
    }
    return ret;
}