A

#include<bits/stdc++.h>
using namespace std;
int n,top,x;
string opt;
int st[100010];
int main(){	
	cin >> n;
	while (n--) {
		cin >> opt;
		if (opt == "push") {
			cin >> x;
			st[++top] = x;
		} else if (opt == "pop") {
			if (top)
				top--;
			else cout << "Empty\n";
		} else if (opt == "top") {
			if (top)
				cout << st[top] << "\n";
			else cout << "Empty\n"; 
		} else if (opt == "isEmpty") {
			if (top == 0) cout << "Yes\n";
			else cout << "No\n";
		} else if (opt == "size") {
			cout << top << "\n";
		}
	}
	return 0; 
}

B

#include<bits/stdc++.h>
using namespace std;
int n,top,x;
string opt;
int st[100010];
int main(){	
	cin >> n;
	while (n--) {
		cin >> opt;
		if (opt == "A") {
			cin >> x;
			st[++top] = x;
		} else if (opt == "U") {
			top--;
		} else if (opt == "F") {
			st[top-1] += st[top];
			top--;
		} else if (opt == "R") {
			swap(st[top], st[top-1]);
		} 
	}
	for (int i=1; i<=top; ++i) cout << st[i] << " ";
	return 0; 
}

C

#include<bits/stdc++.h>
using namespace std;
int n;
string s;

bool check(string s) {
	int top = 0;
	for (auto c:s) {
		if (c == '(') top++;
		else {
			if (top == 0) return false;
			else top--;
		}
	}
	return top == 0;
}

int main(){
	cin >> n;
	for (int i=1; i<=n; ++i) {
		cin >> s;
		if (check(s)) cout << "Yes\n";
		else cout << "No\n";
	} 
	return 0;
}

D

#include<bits/stdc++.h>
using namespace std;

string s;
char st[100010];
int top;

int main(){
	cin >> s;
	for (auto c:s) {
		if (c == 's') {
			if (top && st[top] == 's') top--, c = 'S';
			else st[++top] = 's';
		}
		if (c == 'S') {
			if (top && st[top] == 'S') top--;
			else st[++top] = 'S'; 
		}
//		for (int i=1; i<=top; ++i) cout << st[i];
//		cout << "\n";
	}
	for (int i=1; i<=top; ++i) cout << st[i];
	return 0;
}

E

#include<bits/stdc++.h>
using namespace std;

int T;
int n;
int ok[2010],t[10010],a[2010];


int main(){
	cin >> T;
	while (T--) {
		cin >> n;
		memset(ok, 0, sizeof(ok));
		memset(t, 0, sizeof(t));
		for (int i=1; i<=n; ++i) cin >> a[i];
		for (int i=n; i>=1; --i) {
			if (t[a[i]]) continue;
			else t[a[i]] = 1,cout << a[i] << " ";
		}
		cout << "\n";
	} 
	return 0;
}

F

#include<bits/stdc++.h>
using namespace std;

int n,q,top,stx[2000010],sty[2000010],opt,p;
string d;

int main(){
	cin >> n >> q;
	for (int i=n; i>=1; --i) stx[++top] = i, sty[top] = 0;
	while (q--) {
		cin >> opt;
		if (opt == 1) {
			cin >> d;
			int nx = stx[top], ny = sty[top];
			if (d == "R") nx++;
			else if (d == "L") nx--;
			else if (d == "U") ny++;
			else ny--;
			stx[++top] = nx, sty[top] = ny;
 		} else {
 			cin >> p;
 			cout << stx[top+1-p] << " " << sty[top+1-p] << "\n";
		 }
	}
	return 0;
}