rt,代码CE,请问我错哪儿了？

#include<iostream>
#include<vector>
#include<set>
#include<math.h>
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<time.h>
#include<iterator>
using namespace std;
#define inf 0x3f3f3f3f
#define minf 0x3f
#define inp(x) cin>>x
#define otp(x) cout<<x
#define otp_nl(x) cout<<x<<"\n"
#define otp_sp(x) cout<<x<<" "
#define int long long
#define veci vector<int>
#define str string
#define pb(x) push_back(x)
#define fr(k,len) for(k=0;k<len;k++)
#define nfr(k,len) for(int k=0;k<len;k++)
#define ret return
#define db long double
namespace my_stl{

}

void solve(){
	int q;
	cin>>q;
	set<int>s;
	while(q--){
		int op,x;
		cin>>op;
		switch(op){
			case 1:
			int x;cin>>x;
				auto it=s.find(x);
				int dist=0;
				while(it!=s.begin())dist++,it--;
				cout<<dist<<"\n";
			case 2:
			int x;cin>>x;
				int dis=0;
				auto it1=s.begin();
				for(it1=s.begin();dis<x;it1++,dis++);
				cout<<*it1<<"\n";
			case 3:
			int x;cin>>x;
				auto it2=s.find(x);
				if(it2==x.begin())cout<<"−2147483647\n";
				else{
					it2--;
					cout<<*it2<<"\n";
				}
			case 4:
			int x;cin>>x;
				auto it3=s.find(x);
				if(it3==x.rbegin())cout<<"2147483647\n";
				else{
					it3++;
					cout<<*it3<<"\n";
				}
			case 5:
			int x;cin>>x;
				s.insert(x);
		}
	}
	ret;
}
signed main(){
    int t=1;
	nfr(i,t){
		solve();
	}
	ret 0;
}