Buggy python submission (verdict: Runtime Error):
S = input()
string_list = ["dream", "dreamer", "erase", "eraser"]

dp = []

dp[0] = 1
for i in range(len(S)):
    if dp[i] != 1:
        continue
    for string in string_list:
        if S[i: i + len(string) - 1] == string:
            dp[i + len(string) - 1] = 1

if dp[len(S)] == 1:
    print("Yes")
else:
    print("NO")

Fixed submission:
S = input()

new_S = "".join(list(reversed(S)))
string_list = ["dream", "dreamer", "erase", "eraser"]
reverse_string_list = []
for i in range(len(string_list)):
    reverse_string_list.append("".join(list(reversed(string_list[i]))))

can = True
index = 0
for i in range(len(new_S)):
    if index >= len(new_S):
        break
    can2 = False
    for each_string in reverse_string_list:
        if new_S[index:index + len(each_string)] == each_string:
            index += len(each_string) - 1
            can2 = True
    if can2 is False:
        can = False
        break
    index += 1

if can is True:
    print("YES")
else:
    print("NO")

Buggy python submission (verdict: Runtime Error):
S = input()
string_list = ["dream", "dreamer", "erase", "eraser"]

dp = []

dp[0] = 1
for i in range(len(S)):
    if dp[i] != 1:
        continue
    for string in string_list:
        if S[i: i + len(string) - 1] == string:
            dp[i + len(string) - 1] = 1

if dp[len(S)] == 1:
    print("Yes")
else:
    print("NO")

Fixed submission:
S = input()

new_S = "".join(list(reversed(S)))
string_list = ["dream", "dreamer", "erase", "eraser"]
reverse_string_list = []
for i in range(len(string_list)):
    reverse_string_list.append("".join(list(reversed(string_list[i]))))

can = True
index = 0
for i in range(len(new_S)):
    if index >= len(new_S):
        break
    can2 = False
    for each_string in reverse_string_list:
        if new_S[index:index + len(each_string)] == each_string:
            index += len(each_string) - 1
            can2 = True
    if can2 is False:
        can = False
        break
    index += 1

if can is True:
    print("YES")
else:
    print("NO")

Buggy python submission (verdict: Time Limit Exceeded):
# -*- coding: utf-8 -*-
import time
import re

N = input()
T = ''
char_one = 'dream'
char_two = 'dreamer'
char_three = 'erase' 
char_four = 'eraser'
char_list = [char_one[::-1], char_two[::-1], char_three[::-1], char_four[::-1]]
reverse_string = N[::-1]

start = time.time()
concat_str = ''
i = 0

while i < len(N):
    for string in char_list:
        if reverse_string.find(string) == 0:
            i += len(string)
            reverse_string = re.sub(string, '', reverse_string)
            break
    if i == 0:
       break

if i == len(N):
   print('YES')
else:
   print('NO')


Fixed submission:
S = input()

new_S = "".join(list(reversed(S)))
string_list = ["dream", "dreamer", "erase", "eraser"]
reverse_string_list = []
for i in range(len(string_list)):
    reverse_string_list.append("".join(list(reversed(string_list[i]))))

can = True
index = 0
for i in range(len(new_S)):
    if index >= len(new_S):
        break
    can2 = False
    for each_string in reverse_string_list:
        if new_S[index:index + len(each_string)] == each_string:
            index += len(each_string) - 1
            can2 = True
    if can2 is False:
        can = False
        break
    index += 1

if can is True:
    print("YES")
else:
    print("NO")