qyliang/CodeNanoFix huggingface dataset:
Buggy code:
s = input()
l = ['dreamer', 'eraser', 'dream', 'erase']

for i in l:
    s = s.replace(i,"")

if len(s) == 0:
    print('YES')
else:
    print('NO')


Fixed code:
l = ['eraser', 'erase', 'dreamer', 'dream']
s = input()
for i in l:
    s = s.replace(i, '')
print("YES" if len(s) == 0 else "NO")
Buggy code:
#!/usr/bin/env python

S = input()
S_copy = S
T = []
words = ['dream', 'dreamer', 'erase', 'eraser']

while True:
    match = False
    word_matched = ''
    # check if S_copy ends with word in words
    for word in words:
        if S_copy.endswith(word):
            match = True
            # print('S_copy is', f'{S_copy}')
            # print('ends with', f'{word}')
            if len(word) > len(word_matched):
                # print('this word is longer than previous word_matched')
                # print('word:', f'{word}')
                # print('previous word_matched:', f'{word_matched}')
                word_matched = word

    if match:
        T.insert(0, word_matched)
        # ends with dreamer
        # erasedreamer => erase
        S_copy = S_copy[:-len(word_matched)]
    else:
        break

# print(S)
# print(''.join(T))
if S == ''.join(T):
    print('YES')
else:
    print('No')


Fixed code:
#!/usr/bin/env python

S = input()
S_copy = S
T = []
words = ['dream', 'dreamer', 'erase', 'eraser']

while True:
    match = False
    word_matched = ''
    # check if S_copy ends with word in words
    for word in words:
        if S_copy.endswith(word):
            match = True
            # print('S_copy is', f'{S_copy}')
            # print('ends with', f'{word}')
            if len(word) > len(word_matched):
                # print('this word is longer than previous word_matched')
                # print('word:', f'{word}')
                # print('previous word_matched:', f'{word_matched}')
                word_matched = word

    if match:
        T.insert(0, word_matched)
        # ends with dreamer
        # erasedreamer => erase
        S_copy = S_copy[:-len(word_matched)]
    else:
        break

# print(S)
# print(''.join(T))
if S == ''.join(T):
    print('YES')
else:
    print('NO')
Buggy code:
S = input()
S_list = list(S)

while len(S_list) >= 5 :
    if S_list[0:5] == ['e', 'r', 'a', 's', 'e']:
        if len(S_list) >= 6 :
            if S_list[5] == 'r' :
                del S_list[0:6]
        else:
            del S_list[0:5]
    elif S_list[0:5] == ['d', 'r', 'e', 'a', 'm']:
        if len(S_list) >= 8 :
            if S_list[5:8] == ['e', 'r', 'a'] :
                del S_list[0:5]
        elif len(S_list) >= 7 :
            if S_list[5:7] == ['e', 'r'] :
                del S_list[0:7]
        else :
            del S_list[0:5]
    else:
        print('NO')
        break


if len(S_list) == 0:
    print('YES')
elif 0<len(S_list)<5:
    print('NO')


Fixed code:
S = input()
S_list = list(S)

while len(S_list) >= 5 :
    a = len(S_list)
    if S_list[0:5] == ['e', 'r', 'a', 's', 'e']:
        if a >= 6 :
            if S_list[5] == 'r' :
                del S_list[0:6]
            else:
                del S_list[0:5]
        else:
            del S_list[0:5]
    elif S_list[0:5] == ['d', 'r', 'e', 'a', 'm']:
        if a >= 8 :
            if S_list[5:8] == ['e', 'r', 'a'] :
                del S_list[0:5]
            elif S_list[5:7] == ['e', 'r'] :
                del S_list[0:7]
            else :
                del S_list[0:5]
        elif a >= 7 :
            if S_list[5:7] == ['e', 'r'] :
                del S_list[0:7]
            else:
                del S_list[0:5]
        else :
            del S_list[0:5]
    else:
        print('NO')
        break


if len(S_list) == 0:
    print('YES')
elif 0<len(S_list)<5:
    print('NO')
Buggy code:
import sys
S = str(input())
while S != '':
    print(S)
    if (S[:5] == 'dream' and S[5:11] == 'eraser') or (S[:5] == 'dream' and S[5: 10] == 'erase') or (S[:5] == 'dream' and S[5:] == ''):
        S = S[5:]
    elif S[:5] == 'erase' and S[5] != 'r':
        S = S[5:]
    elif S[:6] == 'eraser':
        S = S[6:]
    elif S[:7] == 'dreamer':
        S = S[7:]
    else:
        print('NO')
        sys.exit()
        break
        
print('YES')


Fixed code:
import sys
S = str(input())
while S != '':
    if (S[:5] == 'dream' and S[5:11] == 'eraser') or (S[:5] == 'dream' and S[5: 10] == 'erase') or (S[:5] == 'dream' and S[5:] == '') or (S[:5] == 'dream' and S[5:10] == 'dream'):
        S = S[5:]
    elif (S[:5] == 'erase' and S[5:] != '' and S[5] != 'r') or (S[:5] == 'erase' and S[5:] == ''):
        S = S[5:]
    elif S[:6] == 'eraser':
        S = S[6:]
    elif S[:7] == 'dreamer':
        S = S[7:]
    else:
        print('NO')
        sys.exit()
        break
        
print('YES')
Buggy code:
import sys
S = input()
S = S[::-1]
while S:
    if S[:3]=="res":
        if S[:6]=="resare":
            S = S[6:]
            print(S)
        else:
            print("NO")
            sys.exit()

    elif S[:3]=="esa":
        if S[:5]=="esare":
            S = S[5:]
            print(S)
        else:
            print("NO")
            sys.exit()
    
    elif S[:3]=="rem":
        if S[:7]=="remaerd":
            S = S[7:]
            print(S)
        else:
            print("NO")
            sys.exit()
        
    elif S[:3]=="mae":
        if S[:5]=="maerd":
            S = S[5:]
            print(S)
        else:
            print("NO")
            sys.exit()
            
    else:
        print("NO")
        sys.exit()
else:
    print("YES")

Fixed code:
import sys
S = input()
S = S[::-1]
while S:
    if S[:3]=="res":
        if S[:6]=="resare":
            S = S[6:]
#             print(S)
        else:
            print("NO")
            sys.exit()

    elif S[:3]=="esa":
        if S[:5]=="esare":
            S = S[5:]
#             print(S)
        else:
            print("NO")
            sys.exit()
    
    elif S[:3]=="rem":
        if S[:7]=="remaerd":
            S = S[7:]
#             print(S)
        else:
            print("NO")
            sys.exit()
        
    elif S[:3]=="mae":
        if S[:5]=="maerd":
            S = S[5:]
#             print(S)
        else:
            print("NO")
            sys.exit()
            
    else:
        print("NO")
        sys.exit()
else:
    print("YES")
Buggy code:
s=input()

def judge():
  cnt=0
  while True:
    if s[cnt:cnt+6]=='eraser':
      cnt+=6
    elif s[cnt:cnt+5]=='erase':
      cnt+=5
    elif s[cnt:cnt+7]=='dreamer':
      cnt+=7
    elif s[cnt:cnt+5]=='dream':
      cnt+=5
    else:
      print('NO')
      exit()
    if cnt==len(s):
      print('YES')
      exit()

judge()

Fixed code:
s=input()
l=len(s)
def judge():
  cnt=0
  while True:
    if s[l-cnt-6:l-cnt]=='eraser':
      cnt+=6
    elif s[l-cnt-5:l-cnt]=='erase':
      cnt+=5
    elif s[l-cnt-7:l-cnt]=='dreamer':
      cnt+=7
    elif s[l-cnt-5:l-cnt]=='dream':
      cnt+=5
    else:
      print('NO')
      exit()
    if cnt==len(s):
      print('YES')
      exit()

judge()
Buggy code:
S = input()[::-1]
import sys
sys.setrecursionlimit(1000)
c = ['maerd', 'remaerd', 'esare', 'resare']

def dfs(s):
    while 1:
        l = len(s)
        if l==0:
            return True
        if l<5:
            return False
        if s[:5] in c:
            s = s[5:]
        elif l>=6 and s[:6]=='resare':
            s = s[6:]
        elif l>=7 and s[:7]=='remaerd':
            s = s[7:]

if dfs(S):
    print('YES')
else:
    print('NO')
        

Fixed code:
S = input()[::-1]
import sys
sys.setrecursionlimit(1000)
c = ['maerd', 'remaerd', 'esare', 'resare']

def dfs(s):
    L = len(s)
    while 1:
        if L==0:
            return True
        if L<5:
            return False
        if s[:5] in c:
            s = s[5:]
            L -= 5
        elif L>=6 and s[:6]=='resare':
            s = s[6:]
            L -= 6
        elif L>=7 and s[:7]=='remaerd':
            s = s[7:]
            L -= 7
        else:
            return False

if dfs(S):
    print('YES')
else:
    print('NO')
Buggy code:
s=input()
s=s+"0000000"
c=0
check=0
while c<len(s):
    if s[c:c+5]=="dream":
        if s[c+5:c+7]=="er":
            if s[c+7]=="a":
                c+=5
            else:
                c+=7
        else:
            c+=5
    elif s[c:c+5]=="erase":
        if s[c+5]=="r":
            c+=6
        else:
            c+=5
    else:
        check+=1
        break
if check==0:
    print("YES")
else:
    print("NO")

Fixed code:
s=input()
n=len(s)
s=s+"0000000"
c=0
check=0
while c<n:
    if s[c:c+5]=="dream":
        if s[c+5:c+7]=="er":
            if s[c+7]=="a":
                c+=5
            else:
                c+=7
        else:
            c+=5
    elif s[c:c+5]=="erase":
        if s[c+5]=="r":
            c+=6
        else:
            c+=5
    else:
        check+=1
        break
if check==0:
    print("YES")
else:
    print("NO")
Buggy code:
import re

s = input()
s = re.sub('dream', '', s)
s = re.sub('dreamer', '', s)
s = re.sub('erase', '', s)
s = re.sub('eraser', '', s)
if len(s) == 0:
    print('YES')
else:
    print('NO')

Fixed code:
import re

s = input()
s = re.sub('eraser', '', s)
s = re.sub('erase', '', s)
s = re.sub('dreamer', '', s)
s = re.sub('dream', '', s)
print('YES' if len(s) == 0 else 'NO')
Buggy code:
S = input()

dp = [False] * (len(S) + 1)
dp[0] = True
T = ['dream', 'dreamer', 'erase', 'eraser']
for i in range(1, len(S) + 1):
    tmp = []
    for t in T:
        if i < len(t):
            continue
        tmp.append(dp[i-len(t)] and t == S[i-len(t): i])
    if any(tmp):
        dp[i] = True
print('Yes' if dp[len(S)] else 'No')

Fixed code:
S = input()

dp = [False] * (len(S) + 1)
dp[0] = True
T = ['dream', 'dreamer', 'erase', 'eraser']
for i in range(1, len(S) + 1):
    tmp = []
    for t in T:
        if i < len(t):
            continue
        tmp.append(dp[i-len(t)] and t == S[i-len(t): i])
    if any(tmp):
        dp[i] = True
print('YES' if dp[len(S)] else 'NO')
Buggy code:
txt = input()
cands = ["dream", "dreamer", "erase", "eraser"]

success = True
while len(txt) > 0:
    flag = False

    for cand in cands:
        subtxt = txt[len(txt) - len(cand):]
        if subtxt == cand:
            txt = txt[:len(txt) - len(cand)]
            flag = True
            print(txt)
            break

    if not flag:
        success = False
        break

if success:
    print("YES")
else:
    print("No")

Fixed code:
txt = input()
cands = ["dream", "dreamer", "erase", "eraser"]

success = True
while len(txt) > 0:
    flag = False

    for cand in cands:
        subtxt = txt[len(txt) - len(cand):]
        if subtxt == cand:
            txt = txt[:len(txt) - len(cand)]
            flag = True
            break

    if not flag:
        success = False
        break

if success:
    print("YES")
else:
    print("NO")
Buggy code:
s = input()
judge = "YES"

s = s.replace("eraser", "0")
s = s.replace("erase", "0")
s = s.replace("dreamer", "0")
s = s.replace("dream", "0")

if not s.isdigit():
  judge = "NO"
print(s)
print(judge)

Fixed code:
s = input()
judge = "YES"

s = s.replace("eraser", "0")
s = s.replace("erase", "0")
s = s.replace("dreamer", "0")
s = s.replace("dream", "0")

if not s.isdigit():
  judge = "NO"
print(judge)
Buggy code:
s = list(input())

a = list("dream")
b = list("dreamer")
c = list("erase")
d = list("eraser")
flag = 0

while(flag == 0):
    print(s)
    if s[-7:] == b:
        del s[-7:]
    elif s[-6:] == d:
        del s[-6:]
    elif s[-5:] == a or s[-5:] == c:
        del s[-5:]
    elif s == []:
        print("YES")
        flag = 1
    else:
        print("NO")
        flag = 1

Fixed code:
s = list(input())

a = list("dream")
b = list("dreamer")
c = list("erase")
d = list("eraser")
flag = 0

while(flag == 0):
    if s[-7:] == b:
        del s[-7:]
    elif s[-6:] == d:
        del s[-6:]
    elif s[-5:] == a or s[-5:] == c:
        del s[-5:]
    elif s == []:
        print("YES")
        flag = 1
    else:
        print("NO")
        flag = 1
Buggy code:
S = input()
strs = list(reversed(S))
rev_S = ''.join(strs)
while True:
  if rev_S[:6] == 'resare'
    rev_S = rev_S[6:]
    continue
  elif rev_S[:7] == 'remaerd':
    rev_S = rev_S[7:]
    continue
  elif rev_S[:5] == 'esare' or rev_S[:5] == 'maerd':
    rev_S = rev_S[5:]
    continue
  else:
    break

if rev_S == '':
  print('YES')
else:
  print('NO')

Fixed code:
S = input()
strs = list(reversed(S))
rev_S = ''.join(strs)
while True:
  if rev_S[:6] == 'resare':
    rev_S = rev_S[6:]
    continue
  elif rev_S[:7] == 'remaerd':
    rev_S = rev_S[7:]
    continue
  elif rev_S[:5] == 'esare' or rev_S[:5] == 'maerd':
    rev_S = rev_S[5:]
    continue
  else:
    break

if rev_S == '':
  print('YES')
else:
  print('NO')
Buggy code:
S = input()
T = ''
words = ['dream', 'dreamer', 'erase', 'eraser']
for i in range(len(words)):
    words[i] = words[i][::-1]
for i in S[::-1]:
    T += i
    for q in words:
        if T == q:
            T = ''
if T == '':
    print('YES')
else:
    print('No')

Fixed code:
S = input()
T = ''
words = ['dream', 'dreamer', 'erase', 'eraser']
for i in range(len(words)):
    words[i] = words[i][::-1]
for i in S[::-1]:
    T += i
    for q in words:
        if T == q:
            T = ''
print('YES' if T == '' else 'NO')
Buggy code:
S=input()
l=len(S)
r=0
list5 = ['dream', 'erase']
list81 = ['dreamdre', 'dreamera', 'erasedre', 'eraseera']
list82 = ['dreamerd', 'dreamere']
list83 = ['eraserdr', 'eraserer']
if l<=4:
    print(False)

while l>=5:
    if S[r:r+5] in list5:
        if r+5==l:
            print(True)
            break
        elif r+5 == l-1:
            if S[r:r+6] == 'eraser':
                print(True)
            else:
                print(False)
            break
        elif r+5 == l-2:
             if S[r:r+7] == 'dreamer':
                 print(True)
             else:
                 print(False)
             break
        elif r+5 == l-3 or r+5 == l-4:
            print(False)
            break
        else:
            if S[r:r+8] in list81:
                r=r+5
            elif S[r:r+8] in list82:
                r=r+7
            elif S[r:r+8] in list83:
                r=r+6
            else:
                print(False)
                break
    else:
        print(False)
        break

Fixed code:
S=input()
l=len(S)
r=0
list5 = ['dream', 'erase']
list81 = ['dreamdre', 'dreamera', 'erasedre', 'eraseera']
list82 = ['dreamerd', 'dreamere']
list83 = ['eraserdr', 'eraserer']
if l<=4:
    print('NO')

while l>=5:
    if S[r:r+5] in list5:
        if r+5==l:
            print('YES')
            break
        elif r+5 == l-1:
            if S[r:r+6] == 'eraser':
                print('YES')
            else:
                print('NO')
            break
        elif r+5 == l-2:
             if S[r:r+7] == 'dreamer':
                 print('YES')
             else:
                 print('NO')
             break
        elif r+5 == l-3 or r+5 == l-4:
            print('NO')
            break
        else:
            if S[r:r+8] in list81:
                r=r+5
            elif S[r:r+8] in list82:
                r=r+7
            elif S[r:r+8] in list83:
                r=r+6
            else:
                print('NO')
                break
    else:
        print('NO')
        break
Buggy code:
def main():
    S = input()
    N = len(S)
    ok = set(['dream','erase','dreamer','eraser'])
    if N < 6 and S not in ok:
        print("NO")
        exit()
    i = 0
    while i < N-5:
        tmp = S[i:i+5]
        if tmp == 'dream':
            if i+6 < N and S[i+5:i+7] == 'er':
                i += 7
            else:
                i += 5
        elif tmp == 'erase':
            if i+5<N and S[i+5] == 'r':
                i += 6
            else:
                i += 5
        else:
            print('NO')
            exit()
    if S[i:] not in ok:
        print('NO')
        exit()
    print('YES')

if __name__ == "__main__":
    main()

Fixed code:
def main():
    S = input()
    N = len(S)
    ok = set(['dream','erase','dreamer','eraser'])
    if N < 8 and S not in ok:
        print("NO")
        exit()
    i = 0
    while i < N-5:
        tmp = S[i:i+5]
        if tmp == 'dream':
            if i+6 < N and S[i+5:i+7] == 'er':
                if i+7<N and S[i+7] == 'a':
                    i += 5
                else:
                    i += 7
            else:
                i += 5
        elif tmp == 'erase':
            if i+5<N and S[i+5] == 'r':
                i += 6
            else:
                i += 5
        else:
            print('NO')
            exit()
    if i < N and S[i:] not in ok:
        print('NO')
        exit()
    print('YES')

if __name__ == "__main__":
    main()
Buggy code:
import sys
s=input()
s=s[::-1]
l=list(["maerd","remaerd","esare","resare"])
i=0
ss=len(s)
while i < ss:
  print(i)
  ok=0
  for j in l:
    print(j)
    if s[i:len(j)] == j:
      ok=1
      i += len(j)
      break
  if ok == 0:
    print("NO")
    sys.exit()
print("YES")



Fixed code:
import sys
s=input()
s=s[::-1]
l=list(["maerd","remaerd","esare","resare"])
i=0
while i < len(s):
  ok=0
  for j in l:
    if s[i:i+len(j)] == j:
      ok=1
      i += len(j)
      break
  if ok == 0:
    print("NO")
    sys.exit()
print("YES")
Buggy code:
S=input()

S=S.replace('dream','')
S=S.replace('dreamer','')
S=S.replace('erase','')
S=S.replace('eraser','')
if len(S)==0:
    print("YES")
else:
    print("NO")

Fixed code:
s = input()

s = s.replace("eraser","")
s = s.replace("erase","")
s = s.replace("dreamer","")
s = s.replace("dream","")
if len(s) == 0:
    print("YES")
else:
    print("NO")
Buggy code:
s = input()
a = ['dream', 'dreamer', 'erase', 'eraser']
for _ in range(4):
  s.replace(a[_], "")
if s=="":
  print("YES")
else:
  print("NO")


Fixed code:
s = input()
a = ['eraser', 'erase', 'dreamer', 'dream']
for i in range(4):
  s = s.replace(a[i], "")
print("YES" if s=="" else "NO")
Buggy code:
s= input()
u= s[::-1]
 
k=["resare","esare","remaerd","maerd"]
 
l=u.replace("resare","")
d=l.replace("esare","")
h=d.replace("remaerd","")
w=h.replace("maerd","")
  
    
if w:
  print("YES")
  
else:
  print("NO")

Fixed code:
s= input()
u= s[::-1]
 
k=["resare","esare","remaerd","maerd"]
 
l=u.replace("resare","")
d=l.replace("esare","")
h=d.replace("remaerd","")
w=h.replace("maerd","")
  
    
if w:
  print("NO")
  
else:
  print("YES")
Buggy code:
s = input()
while(1):
    print(s)
    if s.endswith('dream'):
        s = s[:-5]
    elif s.endswith('dreamer'):
        s = s[:-7]
    elif s.endswith('eraser'):
        s = s[:-6]
    elif s.endswith('erase'):
        s = s[:-5]
    else:
        print("NO")
        quit()
    if s == '':
        break
print("YES")

Fixed code:
s = input()
while(1):
    if s.endswith('dream'):
        s = s[:-5]
    elif s.endswith('dreamer'):
        s = s[:-7]
    elif s.endswith('eraser'):
        s = s[:-6]
    elif s.endswith('erase'):
        s = s[:-5]
    else:
        print("NO")
        quit()
    if s == '':
        break
print("YES")
Buggy code:
s = input()
s = s.replace("dreamer", "")
s = s.replace("dream", "")
s = s.replace("erase", "")
s = s.replace("eraser", "")
if len(s) == 0:
    print("YES")
else:
    print("NO")

Fixed code:
s = input()
s = s.replace("eraser", "")

s = s.replace("erase", "")
s = s.replace("dreamer", "")
s = s.replace("dream", "")
if len(s) == 0:
    print("YES")
else:
    print("NO")
Buggy code:
s = input()
n = len(s)
yn = "YES"

while(len(s) > 0):
    if(s.endswith("dream") or s.endswith("erase")):
        s = s[:(len(s)-5)]
    elif(s.endswith("eraser")):
        s = s[:(len(s)-6)]
    elif(s.endswith("dreamer")):
        s = s[:(len(s)-7)]
    else:
        yn = "NO"

print(yn)

Fixed code:
s = input()
n = len(s)
yn = "YES"

while(len(s) > 0):
    if(s.endswith("dream") or s.endswith("erase")):
        s = s[:(len(s)-5)]
    elif(s.endswith("eraser")):
        s = s[:(len(s)-6)]
    elif(s.endswith("dreamer")):
        s = s[:(len(s)-7)]
    else:
        yn = "NO"
        break

print(yn)
Buggy code:
s=input()
while len(s)>7:
    if s[-5:]=='erase' or s[-5:]=='dream':
        s=s[:-5]
    elif s[-6:]=='eraser':
        s=s[:-6]
    elif s[-7:]=='dreamer':
        s=s[:-7]
    else:
        break
if s=='' or s=='dreamer' or s=='eraser' or s=='erase' or s=='eraser':
    print('YES')
else:
    print('NO')

Fixed code:
s=input()
while len(s)>7:
    if s[-5:]=='erase' or s[-5:]=='dream':
        s=s[:-5]
    elif s[-6:]=='eraser':
        s=s[:-6]
    elif s[-7:]=='dreamer':
        s=s[:-7]
    else:
        break
if s=='' or s=='dreamer' or s=='eraser' or s=='erase' or s=='dream':
    print('YES')
else:
    print('NO')
Buggy code:
from collections import deque

s = input()
q = deque(list(s))

while q:
  if len(q) >= 5:
    subs = q.popleft()+q.popleft()+q.popleft()+q.popleft()+q.popleft()
    if subs != 'erase' and subs != 'dream':
      print('NO')
      exit()
    if subs == 'erase' and len(q) != 0 and q[0] == 'r':
      q.popleft()
    if subs == 'dream' and len(q) == 2 and q[0]+q[1] == 'er':
      q.popleft()
      q.popleft()
    if subs == 'dream' and len(q) >= 3 and q[0]+q[1] == 'er' and q[2] != e:
      q.popleft()
      q.popleft()
  else:
    print('NO')
    exit()
    
print('YES')


Fixed code:
from collections import deque

s = input()
q = deque(list(s))

while q:
  if len(q) >= 5:
    subs = q.popleft()+q.popleft()+q.popleft()+q.popleft()+q.popleft()
    if subs != 'erase' and subs != 'dream':
      print('NO')
      exit()
    if subs == 'erase' and len(q) != 0 and q[0] == 'r':
      q.popleft()
    if subs == 'dream' and len(q) == 2 and q[0]+q[1] == 'er':
      q.popleft()
      q.popleft()
    if subs == 'dream' and len(q) >= 3 and q[0]+q[1] == 'er' and q[2] != 'a':
      q.popleft()
      q.popleft()
  else:
   
    print('NO')
    exit()
    
print('YES')
Buggy code:
S = input()
T = ['dream', 'dreamer', 'erase', 'eraser']


def reverse(t):
    return t[::-1]


RT = [reverse(t) for t in T]
RS = reverse(S)

can = True
i = 0
while i <= len(RS):
    can2 = False
    for j in range(4):
        sizeT = len(RT[j])
        if RT[j] == RS[i:sizeT]:
            i += sizeT
            can2 = True
            break

    if not can2:
        can = False
        break

if can:
    print('YES')
else:
    print('NO')


Fixed code:
S = input()
T = ['dream', 'dreamer', 'erase', 'eraser']


def reverse(t):
    return t[::-1]


RT = [reverse(t) for t in T]
RS = reverse(S)
can = True
i = 0
while i < len(RS):
    can2 = False
    for j in range(4):
        sizeT = len(RT[j])
        if RT[j] == RS[i:i + sizeT]:
            i += sizeT
            can2 = True
            break

    if not can2:
        can = False
        break

if can:
    print('YES')
else:
    print('NO')
Buggy code:
import sys
import resource
sys.setrecursionlimit(10 ** 9)

S = input()
l = []
def dfs(n):
  print(n)
  if n == len(S):
    l.append("YES")
  if n < len(S):
    if S[n:n+5] == "erase":
      dfs(n+5)    
    if S[n:n+5] == "dream":
      dfs(n+5)  
    if S[n:n+6] == "eraser":
      dfs(n+6)              
    if S[n:n+7] == "dreamer":
      dfs(n+7)
dfs(0)
if len(l) == 0:
  l.append("NO")
print(l[0])    

Fixed code:
import sys
import resource
sys.setrecursionlimit(10 ** 9)

S = input()
l = []
def dfs(n):
  if n == len(S):
    l.append("YES")
  if n < len(S):
    if S[n:n+5] == "erase":
      dfs(n+5)    
    if S[n:n+5] == "dream":
      dfs(n+5)  
    if S[n:n+6] == "eraser":
      dfs(n+6)              
    if S[n:n+7] == "dreamer":
      dfs(n+7)
dfs(0)
if len(l) == 0:
  l.append("NO")
print(l[0])
Buggy code:
s=input()
s=s.replace('eraser','')
s=s.replace('erase','')
s=s.replace('dreamer','')
s=s.replace('dream','')
print(s)
if s :
	print('NO')
else:
	print('YES')

Fixed code:
s=input()
s=s.replace('eraser','')
s=s.replace('erase','')
s=s.replace('dreamer','')
s=s.replace('dream','')
#print(s)
if s :
	print('NO')
else:
	print('YES')
Buggy code:
s = input()
s_list = ["eraser","erase","dreamer","dream"]
for i in range(4):
	s.replace(s_list[i],'')
if len(s) == 0:
	print("YES")
else:
	print("NO")

Fixed code:
s = input()
s_list = ["eraser","erase","dreamer","dream"]
for i in range(4):
	s = s.replace(s_list[i],"")
if len(s):
	print("NO")
else:
	print("YES")