HDU 1829 A Bug's Life（带关系的并查集）

#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <cmath>
#include <queue>

using namespace std;
const int M = 1000009;
const int N = 2009;
int n,m;
int fa
;
int rt
;
int finfa(int k)
{
    if(fa[k]==k) return k;
    int t = finfa(fa[k]);
    rt[k] = (rt[k]+rt[fa[k]])%2;
    return fa[k] = t;
}
void un(int a,int b)
{
    int a1 = finfa(a),b1 = finfa(b);
    fa[a1] = b1;
    rt[a1] = (rt[a]+rt[b]+1)%2;
}
struct LT{
    int to,nex;
} L[M<<1];
bool ans ;
void init()
{
    scanf("%d%d",&n,&m);
    ans = false;
    for(int i=0;i<=n;i++) fa[i] = i,rt[i] = 0;
    int f,t;
    for(int i=0;i<m;i++)
    {
        scanf("%d%d",&f,&t);
        if(finfa(f)==finfa(t)&&rt[f]==rt[t])
        ans = true;
        un(f,t);
    }
    if(ans)
        printf("Suspicious bugs found!\n");
    else
        printf("No suspicious bugs found!\n");
    printf("\n");
}
int main()
{
    freopen("in.txt","r",stdin);
    int cas,T= 1;
    scanf("%d",&cas);
    while(cas--)
    {
        printf("Scenario #%d:\n",T++);
        init();
    }
    return 0;
}

#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <cmath>
#include <queue>

using namespace std;
const int M = 1000009;
const int N = 2009;
int n,m;

struct LT{
    int to,nex;
} L[M<<1];
int F
,cnt;
void add(int a,int b)
{
    L[cnt].to = b;
    L[cnt].nex = F[a];
    F[a] = cnt++;
}
int sex
;
queue<int> que;
bool bfs()
{
    while(!que.empty()) que.pop();
    memset(sex,-1,sizeof(sex));
    for(int i=1;i<=n;i++)
    if(sex[i]==-1)
    {
        sex[i] = 0;
        que.push(i);
        while(!que.empty())
        {
            int e = que.front();que.pop();
            for(int i=F[e];i;i=L[i].nex)
            {
                int to = L[i].to;
                if((sex[to]!=-1)&&sex[e]==sex[to])
                return true;
                if(sex[to]==-1)
                {
                    sex[to] = (sex[e]+1)&1;
                    que.push(to);
                }

            }
        }
    }
    return false;
}
int in()
{
    int res=0;char ch=' ';
    while(ch>'9'||ch<'0')ch=getchar();
    res=(ch-'0');
    while((ch=getchar())>='0' && ch<='9' )
        res=res*10+(ch-'0');
    return res;
}
void init()
{
    //scanf("%d%d",&n,&m);
    n = in();m = in();
    cnt = 1;
    memset(F,0,sizeof(F));
    int f,t;
    for(int i=0;i<m;i++)
        f=in(),t=in(),add(f,t),add(t,f);
    if(bfs())
        printf("Suspicious bugs found!\n");
    else
        printf("No suspicious bugs found!\n");
    printf("\n");
}
int main()
{
    freopen("in.txt","r",stdin);
    int cas,T= 1;
    scanf("%d",&cas);
    while(cas--)
    {
        printf("Scenario #%d:\n",T++);
        init();
    }
    return 0;
}