二分图匹配

题意：http://acm.hdu.edu.cn/showproblem.php?pid=5971

把已经告诉你的把能推测的都推测出来有矛盾就“NO”，剩下的跑二分图，矛盾就“NO”，剩下如果还有没有颜色的“NO”。

#define IOS ios_base::sync_with_stdio(0); cin.tie(0);
#include <cstdio>//sprintf islower isupper
#include <cstdlib>//malloc  exit strcat itoa system("cls")
#include <iostream>//pair
#include <fstream>//freopen("C:\Users\13606\Desktop\草稿.txt","r",stdin);
#include <bitset>
//#include <map>
//#include<unordered_map>
#include <vector>
#include <stack>
#include <set>
#include <string.h>//strstr substr
#include <string>
#include <time.h>// srand(((unsigned)time(NULL))); Seed n=rand()%10 - 0~9;
#include <cmath>
#include <deque>
#include <queue>//priority_queue<int, vector<int>, greater<int> > q;//less
#include <vector>//emplace_back
//#include <math.h>
#include <cassert>
//#include <windows.h>//reverse(a,a+len);// ~ ! ~ ! floor
#include <algorithm>//sort + unique : sz=unique(b+1,b+n+1)-(b+1);+nth_element(first, nth, last, compare)
using namespace std;//next_permutation(a+1,a+1+n);//prev_permutation
//******************
int abss(int a);
int lowbit(int n);
int Del_bit_1(int n);
int maxx(int a,int b);
int minn(int a,int b);
double fabss(double a);
void swapp(int &a,int &b);
clock_t __STRAT,__END;
double __TOTALTIME;
void _MS(){__STRAT=clock();}
void _ME(){__END=clock();__TOTALTIME=(double)(__END-__STRAT)/CLOCKS_PER_SEC;cout<<"Time: "<<__TOTALTIME<<" s"<<endl;}
//***********************
#define rint register int
#define fo(a,b,c) for(rint a=b;a<=c;++a)
#define fr(a,b,c) for(rint a=b;a>=c;--a)
#define mem(a,b) memset(a,b,sizeof(a))
#define pr printf
#define sc scanf
#define ls rt<<1
#define rs rt<<1|1
typedef vector<int> VI;
typedef long long ll;
const double E=2.718281828;
const double PI=acos(-1.0);
//const ll INF=(1LL<<60);
const int inf=(1<<30);
const double ESP=1e-9;
const int mod=(int)1e9+7;
const int N=(int)1e4+10;

queue<int>good,bad;
struct node
{
    int u,v;
}edge[N];
vector<int>v[N];
vector<int>mp[N];
int mark[N],color[N];
bool FLAG;

bool bfs(int s)
{
    color[s] = 1; //连通分支的起点可以染1也可以染0
    queue<int>q;
    q.push(s);
    while (!q.empty())
    {
        s = q.front();
        q.pop();
        for (int i = 0; i < (int)mp[s].size(); i ++) {
            int t = mp[s][i];
            if (color[t] == 0) color[t] =3-color[s], q.push(t); //如果相邻顶点未被染色，则加入
            //队列。
            if (color[t] == color[s]) { //如果相邻顶点染相同颜色，则不是二分图。
                return false;
            }
        }
    }
    return true;
}

int main()
{
    int n,m,x,y;
    while(~sc("%d%d%d%d",&n,&m,&x,&y))
    {
        FLAG=1;
        while(!good.empty())good.pop();
        while(!bad.empty())bad.pop();
        for(int i=1;i<=n;++i)v[i].clear(),mp[i].clear(),mark[i]=color[i]=0;
        for(int i=1;i<=m;++i)
        {
            int U,V;
            sc("%d%d",&U,&V);
            edge[i]={U,V};
            v[U].push_back(V);
            v[V].push_back(U);
            mp[U].push_back(V);
            mp[V].push_back(U);
        }
        for(int i=1;i<=x;++i)
        {
            int tt;
            sc("%d",&tt);
            mark[tt]=1;
            good.push(tt);
        }
        for(int i=1;i<=y;++i)
        {
            int tt;
            sc("%d",&tt);
            mark[tt]=2;
            bad.push(tt);
        }
        bool f=0;
        while(!good.empty()||!bad.empty())
        {
            while(!good.empty())
            {
                int now=good.front();good.pop();
                int sz=v[now].size();
                for(int i=sz-1;i>=0;--i)
                {
                    int to=v[now][i];v[now].pop_back();
                    if(mark[to]==0)
                        bad.push(to);
                    else if(mark[to]==1)
                        f=1;
                    else if(mark[to]==2)
                        continue;
                }
            }
            while(!bad.empty())
            {
                int now=bad.front();bad.pop();
                int sz=v[now].size();
                for(int i=sz-1;i>=0;--i)
                {
                    int to=v[now][i];v[now].pop_back();
                    if(mark[to]==0)
                        good.push(to);
                    else if(mark[to]==1)
                        continue;
                    else if(mark[to]==2)
                        f=1;
                }
            }
        }
        if(f)
        {
            pr("NO
");
        }
        else
        {
            for(int i=1;i<=n;++i)
            {
                if(mark[i]==0&&color[i]==0&&mp[i].size()&&!bfs(i))
                {
                    FLAG=0;
                    break;
                }
            }
            for(int i=1;i<=n;++i)
                if(mark[i]==0&&color[i]==0)
                    FLAG=0;
            if(FLAG)
                pr("YES
");
            else
                pr("NO
");
        }
    }
    return 0;
}

/**************************************************************************************/

int maxx(int a,int b)
{
    return a>b?a:b;
}

void swapp(int &a,int &b)
{
    a^=b^=a^=b;
}

int lowbit(int n)
{
    return n&(-n);
}

int Del_bit_1(int n)
{
    return n&(n-1);
}

int abss(int a)
{
    return a>0?a:-a;
}

double fabss(double a)
{
    return a>0?a:-a;
}

int minn(int a,int b)
{
    return a<b?a:b;
}