qyliang/CodeNanoFix huggingface dataset:
Buggy code:
N, x = map(int, input().split())
a = list(map(int, input().split()))
ans = 0

a.sort()

for i in range(N):
    x -= a[i]
    if x < 0:
        print(ans)
        exit()
    else:
        ans += 1

print(N)

Fixed code:
N, x = map(int, input().split())
a = list(map(int, input().split()))
ans = 0

a.sort()

for i in range(N):
    x -= a[i]
    if x >= 0:
        ans += 1

if x>0:
    print(ans-1)
else:
    print(ans)
Buggy code:
n,m=map(int,input().split())
hoge=list(map(int,input().split()))
hoge.sort()
ans=0
for i in range(n):
  if(hoge[i]<=m):
    ans+=1
    m-=hoge[i]
  else:
    break
if(m==0):
  print(ans)
else:
  if(sum(hoge)<m):
    print(n-1)
  else:
    print(ans)

Fixed code:
n,m=map(int,input().split())
hoge=list(map(int,input().split()))
hoge.sort()

if(sum(hoge)<m):
  print(n-1)
  exit()

ans=0
for i in range(n):
  if(hoge[i]<=m):
    ans+=1
    m-=hoge[i]
  else:
    break
print(ans)
Buggy code:
N,x = map(int, input().split())
A = list(map(int, input().split()))
A = sorted(A)
i = 0
tmp =0
while True:
    if i == len(A):
        print(i)
        exit()
    else:
        tmp += A[i]
        if tmp > x or i == len(A):
            print(i)
            exit()
        else:
            i += 1


Fixed code:
N,x = map(int, input().split())
A = list(map(int, input().split()))
A = sorted(A)
i = 0
tmp = 0
while True:
    if i == len(A):
        if  x - tmp == 0:
            print(i)
            exit()
        else:
            print(i - 1)
            exit()
    else:
        tmp += A[i]
        if tmp > x:
            print(i)
            exit()
        else:
            i += 1
Buggy code:
n,x=map(int, input().split())
a=list(map(int, input().split()))
a.sort()
count=0
i=0
while x>0 and i<n:
    x-=a[i]
    if x>=0:count+=1
    i+=1 
print(count)

Fixed code:
n,x=map(int, input().split())
a=list(map(int, input().split()))
a.sort()
count=0
i=0
while x>0 and i<n:
    x-=a[i]
    if x>=0:count+=1
    i+=1 
if x!=0 and count==n:count-=1
print(count)
Buggy code:
a, b = map(int, input().split())
child = sorted(list(map(int, input().split())))
count = 0
print(child)

for i in range(a - 1):
    if b >= child[i]:
        b -= i
        count += 1
if b == child[-1]:
        count += 1

print(count)

Fixed code:
a, b = map(int, input().split())
child = sorted(list(map(int, input().split())))
count = 0

for i in range(a - 1):
    if b >= child[i]:
        b -= child[i]
        count += 1
if b == child[-1]:
        count += 1

print(count)
Buggy code:
n,x=map(int,input().split())
a=list(map(int,input().split()))
a.sort()
c=0
for i in range(len(a)+1):
  if x>0:
    x-=a[i]
    c+=1
  else:
    print(c)
    break

Fixed code:
n,x=map(int,input().split())
a=list(map(int,input().split()))
a.sort()
c=0
for i in range(n):
  if n>=i and x>=a[i]:
    x-=a[i]
    c+=1
    if n==c and x==0:
      print(n)
    if n==c and x!=0:
      print(n-1)
  else:
    print(c)
    break
Buggy code:
N,x = map(int,input().split())
a = list(map(int,input().split()))
a.sort()
ans = 0
judge = [False for i in range(N)]
# print(judge)
for i in range(N):
    if x-a[i]>=0:
        judge[i]=True
        x-=a[i]
temp_count=0
for i in range(N):
    if judge[i]:
        temp_count+=1
# print(judge)
if sum(a)<x:
    print(temp_count-1)
else:
    print(temp_count)


Fixed code:
N,x = map(int,input().split())
a = list(map(int,input().split()))
a.sort()
ans = 0
judge = [False for i in range(N)]
True_X=x
# print(judge)
for i in range(N):
    if x-a[i]>=0:
        judge[i]=True
        x-=a[i]
temp_count=0
for i in range(N):
    if judge[i]:
        temp_count+=1
# print(judge)
if sum(a)<True_X:
    print(temp_count-1)
else:
    print(temp_count)
Buggy code:
N,x = map(int, input().split())
lis = [int(i) for i in input().split()]
lis.sort()
s = 0
ans = 0
for nums in lis:
  if x >= nums:
    x += -nums
    ans += 1
print(ans)
  

Fixed code:
N,x = map(int, input().split())
lis = [int(i) for i in input().split()]
lis.sort()
s = 0
ans = 0
for nums in lis:
  if x >= nums:
    x += -nums
    ans += 1
if ans == N and x != 0:
  ans = ans-1
print(ans)
Buggy code:
N,x = map(int,input().split())
A = sorted(list(map(int,input().split())))
i = 0
while i<N and x>=A[i]:
    x -= A[i]
    i += 1
if x>0:
    i -= 1
print(i)

Fixed code:
N,x = map(int,input().split())
A = sorted(list(map(int,input().split())))
i = 0
while i<N and x>=A[i]:
    x -= A[i]
    i += 1
if x>0 and i==N:
    i -= 1
print(i)
Buggy code:
N,x = map(int,input().split())
A = list(map(int,input().split()))
A.sort()
ans = 0
for i in range(N):
  if A[i] > x :
    print(ans)
    break
  else:
    x -= A[i]
    ans += 1
    if i == N-1:
      print(N-1)
      break


Fixed code:
N,x = map(int,input().split())
A = list(map(int,input().split()))
A.sort()
ans = 0
for i in range(N):
  if A[i] <= x:
    if i == N-1:
      if x == A[i]:
        ans += 1
    else:
      x -= A[i]
      ans += 1
  else:
    break
print(ans)
Buggy code:
n,x=[int(x) for x in input().split()]
a=[int(x) for x in input().split()]

a.sort()
ans=n
s=0
for i in range(n):
    if s>x:
        ans=i
        break
    else:
        s=s+a[i]
if s<x:
    print(ans-1)
else:
    print(ans)

Fixed code:
n,x=[int(x) for x in input().split()]
a=[int(x) for x in input().split()]

a.sort()
s=0
if sum(a)==x:
    ans=n
elif sum(a)<x:
    ans=n-1
else:
    for i in range(n):
        if sum(a[:i+1])>x:
            ans=i
            break;
print(ans)
Buggy code:
import itertools
n, x = map(int, input().split())
a = list(map(int, input().split()))
a.sort(reverse=True)
a = list(itertools.accumulate(a))
cnt=0
for i in range(n):
    if i==n-1 and a[-1]!=x:
        pass
    elif a[i]<=x:
        cnt+=1
        if a[i]==x:
            break
print(cnt)

Fixed code:
import itertools
n, x = map(int, input().split())
a = list(map(int, input().split()))
a.sort()
a = list(itertools.accumulate(a))
cnt = 0
for i in range(n):
    if i==n-1 and a[-1]!=x:
        pass
    elif a[i]<=x:
        cnt+=1
print(cnt)
Buggy code:
N, x = map(int, input().split())
a = list(map(int, input().split()))
ans = 0
a = sorted(a)
for i in range(len(a)):
	if x >= a[i]:
		x -= a[i]
		ans += 1
print(ans)

Fixed code:
N, x = map(int, input().split())
a = list(map(int, input().split()))
a = sorted(a)
sum = 0
ans = 0
for i in range(len(a) - 1):
    sum += a[i]
    if sum > x:
        break
    else:
        ans += 1
sum += a[N-1]
if sum == x:
    ans += 1
print(ans)
Buggy code:
N, x = map(int, input().split())
a = list(map(int, input().split()))
a.sort()
count = 0
for i in range(len(a)):
    if x - a[i] >= 0:
        x -= a[i]
        count += 1
    else:
        break
print(count)

Fixed code:
N, x = map(int, input().split())
a = list(map(int, input().split()))
a.sort()
count = 0
for i in range(len(a)):
    if x - a[i] >= 0:
        x -= a[i]
        count += 1
    else:
        break
if count == N and x  > 0:
    print(count - 1)
else:
    print(count)
Buggy code:
N, x = map(int, input().split())
A = list(map(int, input().split()))
ans = 0
A.sort()
for a in A:
  if x >= a:
    x -= a
    ans += 1
print(ans)
         

Fixed code:
N, x = map(int, input().split())
tmp = x
A = list(map(int, input().split()))
ans = 0
A.sort()
for a in A:
  if x >= a:
    x -= a
    ans += 1
if tmp > sum(A):
  ans -= 1
print(ans)
Buggy code:
n,x=map(int,input().split())
ans=0
a=sorted(list(map(int,input().split())))
for i in range(n):
    x-=a[i]
    if x>=0:
        ans+=1
print(ans)

Fixed code:
n,x=map(int,input().split())
a=sorted(list(map(int,input().split())))
ans=0
for i in range(n):
    if x>=a[i]:
        ans+=1
        x-=a[i]
    else:
        break
if ans == n:
    if x!=0:
        ans-=1
print(ans)
Buggy code:
N, x = map(int, input().split())
a = list(map(int, input().split()))
a.sort()
ans = 0
for i in a:
  if x >= i:
    x -= i
    ans += 1
print(ans)

Fixed code:
N, x = map(int, input().split())
a = list(map(int, input().split()))
a.sort()
ans = 0
for i in a:
  if x >= i:
    x -= i
    ans += 1
if x == 0:
  print(ans)
else:
  print(min(N - 1, ans))
Buggy code:
from bisect import bisect_right

n, x = map(int, input().split())
a = list(map(int, input().split()))
a.sort()
SUM = [a[0]]

for i in range(1, n):
    SUM.append(SUM[-1]+a[i])

if SUM[-1] < x:
    print(n-1)
else:
    print(bisect_right(x, SUM))

Fixed code:
from bisect import bisect_right

n, x = map(int, input().split())
a = list(map(int, input().split()))
a.sort()
SUM = [a[0]]

for i in range(1, n):
    SUM.append(SUM[-1]+a[i])

if SUM[-1] < x:
    print(n-1)
else:
    print(bisect_right(SUM, x))
Buggy code:
n, x = map(int, input().split())
a = list(map(int, input().split()))
if sum(a) < n:
  print(n-1)
  exit()
a.sort()
cnt = 0
i = 0
while a[i] <= n:
  cnt += 1
  n -= a[i]
  i += 1
print(cnt)

Fixed code:
n, x = map(int, input().split())
a = list(map(int, input().split()))
if sum(a) < x:
  print(n-1)
  exit()
a.sort()
cnt = 0
i = 0
while i < n and a[i] <= x:
  cnt += 1
  x -= a[i]
  i += 1
print(cnt)
Buggy code:
from collections import defaultdict
dic = defaultdict(str)
n = int(input())
lst = [input() for _ in range(n)]
last = lst[0]
flag = True
for i in range(1, n):
  if lst[i][0] != last[-1]:
  	flag = False
    break
  dic[lst[i]] += 1
  if dic[lst[i]] > 1
  	flag = False
    break
if flag:
  print("Yes")
else:
  print("No")
  

Fixed code:
from collections import defaultdict
dic = defaultdict(int)
n = int(input())
lst = [input() for _ in range(n)]
last = lst[0]
dic[last] = 1
flag = True
for i in range(1, n):
  if lst[i][0] != last[-1]:
    flag = False
    break
  dic[lst[i]] += 1
  if dic[lst[i]] > 1:
    flag = False
    break
  last = lst[i]
if flag:
  print("Yes")
else:
  print("No")
Buggy code:
l = []

N = int(input())

t = input()
last = t[-1]
l.append(t)

ans = 'Yes'
for _ in range(N-1):
    t = input()
    if t[0] != last or t in l:
        ans = 'No'
print(ans)


Fixed code:
l = []

N = int(input())

t = input()
last = t[-1]
l.append(t)

ans = 'Yes'
for _ in range(N-1):
    t = input()
    if t[0] != last or t in l:
        ans = 'No'
    l.append(t)
    last = t[-1]
print(ans)
Buggy code:
n=int(input())
list=[]
word=input()
list.append(word)
key=word[-1]
flag=True
for i in range(1,n):
    word=input()
    if key==word[0] and (word not in list):
        list.append(word)
        key=word[-1]
    else:
        print("No")
        flag=False
if flag:
    print("Yes")

Fixed code:
n=int(input())
list=[]
word=input()
list.append(word)
key=word[-1]
flag=True
for i in range(1,n):
    word=input()
    if key==word[0] and (word not in list):
        list.append(word)
        key=word[-1]
    else:
        print("No")
        flag=False
        break
if flag:
    print("Yes")
Buggy code:
n = int(input())
words = []
last = ''
ans = 'Yes'
for i in range(n):
  inp = input()
  if inp in words or last != inp[-1]:
    ans = 'No'
    break
  words.append(inp)
  last = inp[-1]
print(ans)

Fixed code:
n = int(input())
start = input()
words = [start]
last = start[-1]
ans = 'Yes'
for i in range(n - 1):
  inp = input()
  if inp in words or last != inp[0]:
    ans = 'No'
    break
  words.append(inp)
  last = inp[-1]
print(ans)
Buggy code:
N=int(input())
answer=[]

for i in range(N):
    answer.append(input())

for j in range(N-1):
    if(answer[j][-1]==answer[j+1][0]):
        if(j==N-2):
            print("Yes")
        else:
            continue
    else:
        print("No")
        break

Fixed code:
N=int(input())
answer=[]

for i in range(N):
    answer.append(input())
    
if(len(set(answer))!=len(answer)):
    print("No")
else:
    for j in range(N-1):
        if(answer[j][-1]==answer[j+1][0]):
            if(j==N-2):
                print("Yes")
            else:
                continue
        else:
            print("No")
            break
Buggy code:
from colecctions import defaultdict

N = int(input())
W = [input().strip() for _ in range(N)]

dic = defaultdict(int)

for i in range(N):
  if i == 0:
    tmp = W[i][-1]
    dic[W[i]] = 1
  else:
    if tmp != W[i][0] or dic[W[i]]:
      print("No")
      break
    else:
      tmp = W[i][-1]
else:
  print("Yes")
    

Fixed code:
from collections import defaultdict
 
N = int(input())
W = [input().strip() for _ in range(N)]
 
dic = defaultdict(int)
 
for i in range(N):
  if i == 0:
    tmp = W[i][-1]
    dic[W[i]] += 1
  else:
    if tmp != W[i][0] or dic[W[i]]:
      print("No")
      break
    else:
      dic[W[i]] += 1
      tmp = W[i][-1]
else:
  print("Yes")
Buggy code:
n=int(input())
s=[input() for i in range(n)];print(s)
if (len(s) == len(set(s))) == 0:
  print("No")
  exit()
for c,d in zip(s[1:],s[0:]):
  if c[-1] == d[0]:
    pass
  else:
    print("No")
    exit()
print("Yes")

Fixed code:
n=int(input())
s=[input() for i in range(n)]
if (len(s) == len(set(s))) == 0:
  print("No")
  exit()
for c,d in zip(s[0:],s[1:]):

  if c[-1] == d[0]:
    pass
  else:
    print("No")
    exit()
print("Yes")
Buggy code:
flag = "Yes"
N = int(input())
W = input()
words = [W]
while len(words) < N:
    a = input()
    words.append(a)
    if W[-1] == a[0] and not(a in words):
        W = a
    else:
        flag = "No"

print(flag)




Fixed code:
flag = "Yes"
N = int(input())
W = input()
words = [W]
while len(words) < N:
    a = input()
    if W[-1] == a[0] and (a not in words):
        W = a
        words.append(a)
    else:
        flag = "No"
        words.append(a)

    #print(flag,words)

print(flag)
Buggy code:
import os
import sys
from collections import defaultdict, Counter, deque
from itertools import product, permutations,combinations, accumulate
from operator import itemgetter
from bisect import bisect_left,bisect
from heapq import heappop,heappush,heapify
from math import ceil, floor, sqrt
from copy import deepcopy


def main():
    n = int(input())
    vectoer = []
    flag = True
    for i in range(n):
        s = input()
        vectoer.append(s)

    if len(vectoer) != len(set(vectoer)):
        flag = False

    print(n)
    for i in range(n-1):
        if vectoer[i][-1] !=  vectoer[i+1][0]:
            flag = False
            break

    if flag:
        print("Yes")
    else:
        print("No")
    

if __name__ == '__main__':
	main()


Fixed code:
import os
import sys
from collections import defaultdict, Counter, deque
from itertools import product, permutations,combinations, accumulate
from operator import itemgetter
from bisect import bisect_left,bisect
from heapq import heappop,heappush,heapify
from math import ceil, floor, sqrt
from copy import deepcopy


def main():
    n = int(input())
    vectoer = []
    flag = True
    for i in range(n):
        s = input()
        vectoer.append(s)

    if len(vectoer) != len(set(vectoer)):
        flag = False
        
    for i in range(n-1):
        if vectoer[i][-1] !=  vectoer[i+1][0]:
            flag = False
            break

    if flag:
        print("Yes")
    else:
        print("No")
    

if __name__ == '__main__':
	main()
Buggy code:
N = int(input())

word = [word.append(input()) for i in range(N)]


for i in range(1, N):
    if word[i][0] != word[i - 1][-1] or word.count(word[i]) != 1:
        print('No')
        exit()

print('Yes')



Fixed code:
N = int(input())

word = []
for i in range(N):
    word.append(input())

for i in range(N - 1):
    if word.count(word[i]) != 1:
        print('No')
        exit()

for i in range(1, N):
    if word[i][0] != word[i - 1][-1]:
        print('No')
        exit()

print('Yes')
Buggy code:
n=int(input())
ans='Yes'
s=input()
alist=[s]
for i in range(n-1):
    new=input()
    if new in alist:ans='No'
    if new[0]!=alist[-1][-1]:ans='No'
print(ans)

Fixed code:
n=int(input())
ans='Yes'
s=input()
alist=[s]
for i in range(n-1):
    new=input()
    if new in alist:ans='No'
    if new[0]!=alist[-1][-1]:ans='No'
    alist.append(new)
print(ans)
Buggy code:
from collections import *
n=int(input())
l=[]
for i in range(n):
    l.append(input())
f=0
c=Counter(l)
for i in c.values():
    if(i>1):
        f=1
        break
if(f==1):
    print("No")
else:
    d=0
    for i in range(1,n):
        if(l[i-1][-1]!=l[i][0]):
            d=1
            break
    if(f==1):
        print("No")
    else:
        print("Yes")


Fixed code:
from collections import *
n=int(input())
l=[]
for i in range(n):
    l.append(input())
f=0
c=Counter(l)
for i in c.values():
    if(i>1):
        f=1
        break
if(f==1):
    print("No")
else:
    d=0
    for i in range(1,n):
        if(l[i-1][-1]!=l[i][0]):
            d=1
            break
    if(d==1):
        print("No")
    else:
        print("Yes")
Buggy code:
N = int(input())

word_list = []
f = 0
for i, n in enumerate(range(N)):
  s = input()
  if i == 0:
    pre = s[-1]
    continue
  if s in word_list:
    f = 1
    break
  if s[-1] != pre:
    f = 1
    break
if f == 1:
  print("No")
else:
  print("Yes")

Fixed code:
N = int(input())

word_list = []
f = 0
for i, n in enumerate(range(N)):
  s = input()
  if i == 0:
    pre = s[-1]
    word_list.append(s)
    continue
  if s in word_list:
    f = 1
    break
  if s[0] != pre:
    f = 1
    break
  pre = s[-1]
  word_list.append(s)
if f == 1:
  print("No")
else:
  print("Yes")
Buggy code:
N = int(input_[0])
S=[]

for n in range(N):
    s=input_[n+1]
    S.append(s)
S_set=set(S)

ans='Yes'
if len(S_set) != N:
    ans='No'

for n in range(N-1):
    n_ = n+1
    s_0=S[n][-1]
    s_1=S[n_][0]
    
    if s_0 != s_1:
        ans='No'
print(ans)

Fixed code:
N = int(input())
S=[]

for n in range(N):
    s=input()
    S.append(s)
S_set=set(S)

ans='Yes'
if len(S_set) != N:
    ans='No'

for n in range(N-1):
    n_ = n+1
    s_0=S[n][-1]
    s_1=S[n_][0]
    
    if s_0 != s_1:
        ans='No'
print(ans)
Buggy code:
n=int(input())
temp=str(input())
templ=list(temp)
tempb=templ[len(templ)-1]
w=[0]*n
w[0]=temp
for i in range(0,n-1):
  temp=str(input())
  templ=list(temp)
  if temp in w or tempb!=templ[len(templ)-1]:
    print("No")
    break
else:
  print("Yes")
  

Fixed code:
n=int(input())
temp=str(input())
templ=list(temp)
tempb=templ[len(templ)-1]
w=[0]*n
w[0]=temp
for i in range(0,n-1):
  temp=str(input())
  templ=list(temp)
  if temp in w or tempb!=templ[0]:
    print("No")
    break
  tempb=templ[len(templ)-1]
  w[i+1]=temp
else:
  print("Yes")
Buggy code:
import sys
import math
import bisect

def solve():
    n = int(input())
    my_set = set()
    for i in range(n):
        if i == 0:
            s = input()
        else:
            pre = s
            s = input()
            if pre[-1] != s[0]:
                return False
            if s in my_set:
                return False
            my_set.add(s)
    return True

def main():
    if solve():
        print('Yes')
    else:
        print('No')

if __name__ == "__main__":
    main()


Fixed code:
import sys
import math
import bisect

def solve():
    n = int(input())
    my_set = set()
    for i in range(n):
        if i == 0:
            s = input()
            my_set.add(s)
        else:
            pre, s = s, input()
            if pre[-1] != s[0]:
                return False
            if s in my_set:
                return False
            my_set.add(s)
    return True

def main():
    if solve():
        print('Yes')
    else:
        print('No')

if __name__ == "__main__":
    main()
Buggy code:
n= int(input())

list=[]
for i in range(n):
  list.append(input())
  
import collections
c=collections.Counter(list)
t=0
for i in range(n-1):
  if list[i][len(list[i])-1]==list[i+1][0]:
    t += 1
  else:
    pass

if t == n and c == n:
  print("Yes")
else:
  print("No")


Fixed code:
n= int(input())

list=[]
for i in range(n):
  list.append(input())
  
import collections
c=collections.Counter(list)
t=0
for i in range(n-1):

  if list[i][len(list[i])-1]==list[i+1][0]:
    
    t += 1
  else:
    pass

if t == n-1 and len(c) == n:
  print("Yes")
else:
  print("No")
Buggy code:
n=int(input())
s=[input() for i in range(n)]
p=list(s[0])[0]
from collections import Counter
c=Counter(s)
if sum(c.values())!=n:
    print("No")
    exit()
else:
    for i in s:
        a=list(i)[0]
        b=list(i)[-1]
        if p==a:
            p=b
        else:
            print("No")
            exit()
print("Yes")
        

Fixed code:
n=int(input())
s=[input() for i in range(n)]
p=list(s[0])[0]
from collections import Counter
c=Counter(s)
if [1 for i in range(n)]!=list(c.values()):
    print("No")
    exit()
else:
    for i in s:
        a=list(i)[0]
        b=list(i)[-1]
        if p==a:
            p=b
        else:
            print("No")
            exit()
print("Yes")
Buggy code:
import sys

N = int(input())
W = list(input() for _ in range(N))

cnt = 0
if len(set(W)) == len(W):
	for i in range(N-1): 
		if W[i][0] != W[i+1][-1]:
			print('No')
			sys.exit()
		else:
			print('Yes')
else:
	print('No')

Fixed code:
import sys

N = int(input())
W = list(input() for _ in range(N))

if len(set(W)) == N:
	for i in range(N-1):
		a = W[i]
		b = W[i+1] 
		if a[-1] != b[0]:
			print('No')
			sys.exit()
	print('Yes')
else:
	print('No')
Buggy code:
n = int(input())
w = [input() for i in range(n)]
if n == len(set(w)) and w[i-1][-1] == w[i][0] for i in range(1,n):
    print('Yes')
else:
    print('No')

Fixed code:
n = int(input())
w = [input() for i in range(n)]
if all(n == len(set(w)) and w[i-1][-1] == w[i][0] for i in range(1,n)):
       print('Yes')
else:
       print('No')
Buggy code:
n = int(input())
w = [input() for i in range(n)]
if len(set(w)) == n:
    for i in range(1, n):
        s0 = list(w[i - 1])
        s1 = list(w[i])
        if s1[0] == s0[-1]:
            pass
        else:
            print("NO")
            exit()
    print("Yes")
else:
    print("No")

Fixed code:
n = int(input())
w = [input() for i in range(n)]
if len(set(w)) == n:
    for i in range(1, n):
        s0 = list(w[i - 1])
        s1 = list(w[i])
        if s1[0] == s0[-1]:
            pass
        else:
            print("No")
            exit()
    print("Yes")
else:
    print("No")
Buggy code:
n=int(input())
a=input()
l=[a]
ans="Yes"
for i in range(n-1):
    w=input()
    a=w
    if (a[-1]!=w[0]) or (w in l ):
        ans="No"
    l.append(w)
print(ans)

Fixed code:
n=int(input())
a=input()
l=[a]
ans="Yes"
for i in range(n-1):
    w=input()
    if (a[-1]!=w[0]) or (w in l ):
        ans="No"
    l.append(w)
    a=w
print(ans)
Buggy code:
n,w,temp = int(input()),[],[]
for i in range(n):
    w.append(input())
    print(w[-1])
    if w[-1] in temp:
        print("No")
        exit()
    else:
        temp.append(w[-1])
    if i > 1 and w[i-1][0] != w[i][-1]:
        print("No")
        exit()
print("Yes")

Fixed code:
n,w,temp = int(input()),[],[]
for i in range(n):
    w.append(input())
    if w[-1] in temp:
        print("No")
        exit()
    else:
        temp.append(w[-1])
    if i>0 and w[i-1][-1] != w[i][0]:
        print("No")
        exit()
print("Yes")
Buggy code:
n = int(input())
words = [input() for _ in range(n)]
print("Yes" if all([y[0] == x[-1] for x, y in zip(words, words[1:]) and len(set(words)) == n else "No")

Fixed code:
n = int(input())
words = [input() for _ in range(n)]
print("Yes" if all([y[0] == x[-1] for x, y in zip(words, words[1:])]) and len(set(words)) == n else "No")
Buggy code:
N = int(input())
W = [input() for i in range(N)]

for idx,val in enumerate(W):
    if idx == 0:
        continue
    a = W[idx-1][-1:] 
    b = val[:1]
    if W[idx-1][:-1] != val[1:] or W.count(val) > 0:
        print('No')
        exit()
print('Yes')



Fixed code:
N = int(input())
W = [input() for i in range(N)]

for idx,val in enumerate(W):
    if idx == 0:
        continue
    if W[idx-1][-1] != val[0] or W.count(val) > 1:
        print('No')
        exit()
print('Yes')
Buggy code:
N = int(input())
Mylog = []
cnt = 0
x = list(input())
Mylog.append(x)
for i in range(1,N):
  x = list(input())
  Mylog.append(x)
  if (x in Mylog) or (Mylog[i-1][-1] != Mylog[i][0]):
    cnt += 1
print("Yes" if cnt==0 else "No")

Fixed code:
N = int(input())
Mylog = []
cnt = 0
x = list(input())
Mylog.append(x)
for i in range(1,N):
  x = list(input())
  Mylog.append(x)
  if (x in Mylog[:-1]) or (Mylog[i-1][-1] != Mylog[i][0]):
    cnt += 1

print("Yes" if cnt==0 else "No")