Problem: Takahashi has a string S consisting of lowercase English letters.  Starting with this string, he will produce a new one in the procedure given as follows.  The procedure consists of Q operations. In Operation i (1 \leq i \leq Q), an integer T_i is provided, which means the following:    * If T_i = 1: reverse the string S.    * If T_i = 2: An integer F_i and a lowercase English letter C_i are additionally provided.      * If F_i = 1 : Add C_i to the beginning of the string S.     * If F_i = 2 : Add C_i to the end of the string S.  Help Takahashi by finding the final string that results from the procedure.

Submission attempts (in order):
S = list(input())
Q = int(input())
l_list = []
r_list = []
for i in range(Q):
    A = list(map(str, input().split()))
    if len(A)==1:
        flag = not flag
    else:
        if flag:
            if A[1]=="1":
                l_list.insert(0, A[2])
            else:
                r_list.append(A[2])
        else:
            if A[1]=="1":
                r_list.insert(0, A[2])
            else:
                l_list.append(A[2])
if flag:
    print("".join(l_list)+"".join(S)+"".join(r_list))
else:
    print("".join(r_list[::-1])+"".join(S[::-1])+"".join(l_list[::-1]))

S = list(input())
Q = int(input())
l_list = []
r_list = []
for i in range(Q):
    A = list(map(str, input().split()))
    if len(A)==1:
        flag = not flag
    else:
        if flag:
            if A[1]=="1":
                l_list.insert(0, A[2])
            else:
                r_list.append(A[2])
        else:
            if A[1]=="1":
                r_list.insert(0, A[2])
            else:
                l_list.append(A[2])
if flag:
    print("".join(l_list)+"".join(S)+"".join(r_list))
else:
    print("".join(r_list[::-1])+"".join(S[::-1])+"".join(l_list[::-1]))

S = list(input())
Q = int(input())
l_list = []
r_list = []
flag = True
for i in range(Q):
    A = list(map(str, input().split()))
    if len(A)==1:
        flag = not flag
    else:
        if flag:
            if A[1]=="1":
                l_list.appendleft(A[2])
            else:
                r_list.append(A[2])
        else:
            if A[1]=="1":
                r_list.append(A[2])
            else:
                l_list.appendleft(A[2])
if flag:
    print("".join(l_list)+"".join(S)+"".join(r_list))
else:
    print("".join(r_list[::-1])+"".join(S[::-1])+"".join(l_list[::-1]))

S = list(input())
Q = int(input())
l_list = []
r_list = []
flag = True
for i in range(Q):
    A = list(map(str, input().split()))
    if len(A)==1:
        flag = not flag
    else:
        if flag1:
            if A[1]=="1":
                l_list.appendleft(A[2])
            else:
                r_list.append(A[2])
        else:
            if A[1]=="1":
                r_list.append(A[2])
            else:
                l_list.appendleft(A[2])
if flag:
    print("".join(l_list)+"".join(S)+"".join(r_list))
else:
    print("".join(r_list[::-1])+"".join(S[::-1])+"".join(l_list[::-1]))

from collections import deque
S = deque(input())
Q = int(input())
flag = True
for i in range(Q):
    A = list(map(str, input().split()))
    if len(A)==1:
        flag = not flag
    else:
        if flag:
            if A[1]=="1":
                S.appendleft(A[2])
            else:
                S.append(A[2])
        else:
            if A[1]=="1":
                S.append(A[2])
            else:
                S.appendleft(A[2])
S = "".join(S)
if flag:
    print(S)
else:
    print(S[::-1])

Verdicts: Runtime Error

Runtime Error

Runtime Error

Runtime Error

Accepted