二分图最大匹配

#include <bits/stdc++.h>

using namespace std;

const int N = 2e5 + 10;

int e[N], h[N], ne[N], idx;

void add(int a, int b)
{
    e[++ idx] = b, ne[idx] = h[a], h[a] = idx;
}

int co[N];

bool check(int u, int c)
{
    co[u] = c;
    
    for(int i = h[u]; ~i; i = ne[i])
    {
        int j = e[i];
        if(!co[j])
        {
            if(!check(j, 3 - c)) return false;
        }
        else if(co[j] == c) return false;
    }
    
    return true;
}

int main()
{
    int n, m;
    
    cin >> n >> m;
    
    memset(h, -1, sizeof h);
    
    for(int i = 1; i <= m; i ++)
    {
        int a, b;
        cin >> a >> b;
        add(a, b), add(b, a);
    }
    
    for(int i = 1; i <= n; i ++)
    {
        if(!co[i])
        {
            if(!check(i, 1))
            {
                cout << "No\n";
                return 0;
            }
        }
    }
    
    cout << "Yes\n";
    
    return 0;
}