本人code(WA三个，RE三个)：

#include<bits/stdc++.h>
using namespace std;
bool a[100005];
int main(){
	int n;
	cin>>n;
	int minx=100000,maxy=0;
	for (int i=1;i<=n;i++){
		int x,y;
		cin>>x>>y;
		minx=min(minx,x);
		maxy=max(maxy,y);
		for (int j=x;j<=y;j++)a[j]=true;
	}
	int ans1=0,ans2=0;
	int x=minx;
	while (x<=maxy){
		x--;
		if (a[x]){
			int sum=0;
			while (a[x]&&x<maxy)x++,sum++;
			sum--;
			ans1=max(ans1,sum);
		}
		if (!a[x]){
			int sum=0;
			while (!a[x]&&x<maxy)x++,sum++;
			sum--;
			ans2=max(ans2,sum);
		}
		x++;
	}
	cout<<ans1<<" "<<ans2+2<<"\n";
	return 0;
}