实在没搞懂，去同步超一大堆，scanf稳过 大佬求解

#include<bits/stdc++.h>
#define F(a,b) for(int i=(a);i<=(b);i++)
#define DF(a,b) for(int i=(b);i>=(a);i--)
using namespace std;
int a[22222];
int get(int x)
{
	if(a[x]==x) return x;
	return a[x]=get(a[x]);
}
int main()
{
	int n,m;
	cin>>n>>m;
	for(int i=1;i<=n;i++)
	{
		a[i]=i;
	}
	for(int i=1;i<=m;i++)
	{
		int x,y;
		scanf("%d%d",&x,&y);
		a[get(x)]=a[get(y)];
	}
	int t;
	scanf("%d",&t);
	while(t--)
	{
		int x,y;
		scanf("%d%d",&x,&y);
		if(a[get(x)]==a[get(y)])
		{
			cout<<"Yes\n";
		}
		else
		{
			cout<<"No\n";
		}
	}
	return 0;
}

其实不用ios::sync_with_stdio(false);的。 我一开始用了ios但是一直错 我把ios删了后竟然对了 其实只要把cin改成scanf就行了 下面上代码

using namespace std;
int a[200005];
int find(int x)
{
	if(a[x]==x) return x;
	return a[x]=find(a[x]);
}
int main()//整体和并查集差不多
{
	int n, m, x, y;
	cin>>n>>m;
	for(int i=1; i<=n; i++)
		a[i]=i;
	for(int i=0; i<m; i++)
	{
		scanf("%d%d",&x,&y);//cin改scanf
		a[find(x)]=a[find(y)];
	}
	int q;
	cin>>q;
	for(int i=0; i<q; i++)
	{
		scanf("%d%d",&x,&y);//cin改scanf
		if(a[find(x)]==a[find(y)]) cout<<"Yes\n";
		else cout<<"No\n";
	}
	return 0;
}

亲测能过，大家给个赞吧

请使用\n代替endl,并使用关同步

#include <bits/stdc++.h>
#define IOS ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);
#define re register
using namespace std;
typedef long long ll;
int fth[1000010], n, m, q, x, y, tx, ty;
int fnd(int t)
{
	return (fth[t]==t?t:fth[t]=fnd(fth[t]));
}
int main()
{
	IOS;
	cin>>n>>m;
	for(int i=0; i<=n; i++) fth[i]=i;
	for(int i=0; i<m; i++)
	{
		cin>>x>>y;
		tx=fnd(x), ty=fnd(y);
		if(tx!=ty) fth[ty]=tx;
	}
	cin>>q;
	while(q--)
	{
		cin>>x>>y;
		cout<<(fnd(x)==fnd(y)?"Yes\n":"No\n");
	}
	return 0;
}

#include<bits/stdc++.h> using namespace std; int fa[20005],n,m; int get(int x){ return (fa[x]==x?x:fa[x]=get(fa[x])); } int main(){ ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0); cin>>n>>m; for(int i=1;i<=n;i++)fa[i]=i; for(int i=1;i<=m;i++){ int x,y; cin>>x>>y; fa[get(x)]=get(y); } cin>>m; for(int i=1;i<=m;i++){ int x,y; cin>>x>>y; if(get(x)==get(y))cout<<"Yes"; else cout<<"No"; cout<<endl; } return 0; }

#include<bits/stdc++.h>
using namespace std;
int fa[20005],n,m;
int get(int x){
	return (fa[x]==x?x:fa[x]=get(fa[x]));
}
int main(){
	ios_base::sync_with_stdio(false);
	cin.tie(0);
	cout.tie(0);
	cin>>n>>m;
	for(int i=1;i<=n;i++)fa[i]=i;
	for(int i=1;i<=m;i++){
		int x,y;
		cin>>x>>y;
		fa[get(x)]=get(y);
	}
	cin>>m;
	for(int i=1;i<=m;i++){
		int x,y;
		cin>>x>>y;
		if(get(x)==get(y))cout<<"Yes";
		else cout<<"No";
		cout<<"\n";
	}
	return 0;
}

#include<bits/stdc++.h> using namespace std; int fa[20005],n,m; int get(int x){ return (fa[x]==x?x:fa[x]=get(fa[x])); } int main(){ ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0); cin>>n>>m; for(int i=1;i<=n;i++)fa[i]=i; for(int i=1;i<=m;i++){ int x,y; cin>>x>>y; fa[get(x)]=get(y); } cin>>m; for(int i=1;i<=m;i++){ int x,y; cin>>x>>y; if(get(x)==get(y))cout<<"Yes"; else cout<<"No"; cout<<endl; } return 0; }