题目

种类并查集

#include<bits/stdc++.h>
using namespace std;
int op,x,y,n,m,i,v[150003],ans;
int find(int x){
    return v[x]==x?x:v[x]=find(v[x]);
}
int main(){
    cin>>n>>m;
    for (i=1;i<=3*n;i++) v[i]=i;
    for (i=1;i<=m;i++){
        scanf("%d%d%d",&op,&x,&y);
        if (x>n || y>n){
            ans++;
            continue;
        }
        if (op==1)
            if (v[find(x)]==v[find(y+n)] || v[find(x+n)]==v[find(y)]) ans++;
            else v[find(x)]=v[find(y)],v[find(x+n)]=v[find(y+n)],v[find(x+2*n)]=v[find(y+2*n)];
        if (op==2)
            if (v[find(x)]==v[find(y)] || v[find(x)]==v[find(y+n)]) ans++;
            else v[find(x+n)]=v[find(y)],v[find(x+2*n)]=v[find(y+n)],v[find(x)]=v[find(y+2*n)];
    }
    cout<<ans;
}

带权并查集

#include<bits/stdc++.h>
using namespace std;
const int N=50002;
int n,m,i,d,x,y,ans,fa[N],r[N];
inline char gc(){
    static char buf[100000],*p1=buf,*p2=buf;
    return p1==p2&&(p2=(p1=buf)+fread(buf,1,100000,stdin),p1==p2)?EOF:*p1++;
}
inline int rd(){
    int x=0,fl=1;char ch=gc();
    for (;ch<48||ch>57;ch=gc())if(ch=='-')fl=-1;
    for (;48<=ch&&ch<=57;ch=gc())x=(x<<3)+(x<<1)+(ch^48);
    return x*fl;
}
int find(int x){
    if (x==fa[x]) return x;
    int t=find(fa[x]);
    (r[x]+=r[fa[x]])%=3;
    fa[x]=t;
    return t;
}
bool Union(int d,int x,int y){
    int rx=find(x),ry=find(y);
    if (rx==ry) return (r[x]-r[y]+3)%3!=d;
    fa[rx]=ry;
    r[rx]=(r[y]-r[x]+d+3)%3;
    return 0;
}
int main(){
    n=rd(),m=rd();
    for (i=1;i<=n;i++) fa[i]=i;
    for (;m--;){
        d=rd(),x=rd(),y=rd();
        if (x>n || y>n || d==2 && x==y) ans++;
        else ans+=Union(d-1,x,y);
    }
    printf("%d",ans);
}