Buggy python submission (verdict: Time Limit Exceeded):
def main():
    N = int(input())
    A = list(map(int,input().split()))

    count = 0
    flag = False

    '''
    for i in A:
        if(A.count(i) > 1):
            flag = True
            break

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

    for i in A:
        for j in A:
            if(i == j):
                count += 1
            if(count > 1):
                flag = True
                break
        count = 0

        if(flag):
            break

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

if __name__ == "__main__":
    main()

Fixed submission:
def main():
    N = int(input())
    A = list(map(int,input().split()))

    count = 0
    flag = False

    set_A = set(A)

    if(len(set_A) == len(A)):
        print('YES')
    else:
        print('NO')
        
    '''
    for i in A:
        if(A.count(i) > 1):
            flag = True
            break

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

'''
    for i in A:
        for j in A:
            if(i == j):
                count += 1
            if(count > 1):
                flag = True
                break
        count = 0

        if(flag):
            break

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

if __name__ == "__main__":
    main()

Buggy python submission (verdict: Time Limit Exceeded):
def main():
    N = int(input())
    A = list(map(int,input().split()))

    count = 0
    flag = False

    for i in A:
        if(A.count(i) > 1):
            flag = True
            break

    if(flag):
        print('NO')
    else:
        print('YES')
    '''
    for i in A:
        for j in A:
            if(count == 2):
                flag = True
                break
            if(i == j):
                count += 1
        count = 0

        if(flag):
            break

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

if __name__ == "__main__":
    main()

Fixed submission:
def main():
    N = int(input())
    A = list(map(int,input().split()))

    count = 0
    flag = False

    set_A = set(A)

    if(len(set_A) == len(A)):
        print('YES')
    else:
        print('NO')
        
    '''
    for i in A:
        if(A.count(i) > 1):
            flag = True
            break

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

'''
    for i in A:
        for j in A:
            if(i == j):
                count += 1
            if(count > 1):
                flag = True
                break
        count = 0

        if(flag):
            break

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

if __name__ == "__main__":
    main()

Buggy python submission (verdict: Time Limit Exceeded):
def main():
    N = int(input())
    A = list(map(int,input().split()))

    count = 0
    flag = False

    for i in A:
        if(A.count(i) > 1):
            flag = True
            break

    if(flag):
        print('NO')
    else:
        print('YES')
    '''
    for i in A:
        for j in A:
            if(count == 2):
                flag = True
                break
            if(i == j):
                count += 1
        count = 0

        if(flag):
            break

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

if __name__ == "__main__":
    main()

Fixed submission:
def main():
    N = int(input())
    A = list(map(int,input().split()))

    count = 0
    flag = False

    set_A = set(A)

    if(len(set_A) == len(A)):
        print('YES')
    else:
        print('NO')
        
    '''
    for i in A:
        if(A.count(i) > 1):
            flag = True
            break

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

'''
    for i in A:
        for j in A:
            if(i == j):
                count += 1
            if(count > 1):
                flag = True
                break
        count = 0

        if(flag):
            break

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

if __name__ == "__main__":
    main()