RE 了，求助

#include<bits/stdc++.h>
using namespace std;
const int N=5e4+5;
int a[N];
vector<int>v;
int main(){
	int n=0;
	while(scanf("%d",&a[n++])!=-1);
	n--;
	for(int i=n-1;~i;i--){
		if(v.empty()||v.back()<=a[i]) v.push_back(a[i]);
		else *upper_bound(v.begin(),v.end(),a[i])=a[i];
	}
	cout<<v.size()<<"\n";
	v.clear();
	for(int i=0;i<n;i++){
		if(v.empty()||v.back()<a[i]) v.push_back(a[i]);
		else *lower_bound(v.begin(),v.end(),a[i])=a[i];
	}
	cout<<v.size();
	return 0;
}