The first input array is the key to the correct answers to an exam, like ["a", "a", "b", "d"]. The second one contains a student's submitted answers. 

The two arrays are not empty and are the same length. Return the score for this array of answers, giving +4 for each correct answer, -1 for each incorrect answer, and +0 for each blank answer, represented as an empty string (in C the space character is used).

If the score < 0, return 0.

For example:
```
checkExam(["a", "a", "b", "b"], ["a", "c", "b", "d"]) → 6
checkExam(["a", "a", "c", "b"], ["a", "a", "b",  ""]) → 7
checkExam(["a", "a", "b", "c"], ["a", "a", "b", "c"]) → 16
checkExam(["b", "c", "b", "a"], ["",  "a", "a", "c"]) → 0
```

Difficulty: introductory

Starter code:

def check_exam(arr1,arr2):
	

Solutions:
def check_exam(arr1, arr2):
    return max(0, sum(4 if a == b else -1 for a, b in zip(arr1, arr2) if b))

def check_exam(arr1,arr2):
    score = 0
    for i in range(0,4):
        if arr1[i] == arr2[i]:
            score += 4
        elif arr1[i] == "" or arr2[i] == "":
            score += 0
        else: 
            score -= 1
    
    return score if score >= 0  else 0
  


def check_exam(arr1,arr2):
    score=0
    for i in range(len(arr1)):
        if arr2[i]!='':
            if arr2[i]==arr1[i]:
                score=score+4
            else:
                score=score-1
    return (score if score>0 else 0)

def check_exam(arr1,arr2):
    score = 0
    for i in range(len(arr1)):
        if arr1[i] == arr2[i]:
            score += 4
        elif arr1[i] != arr2[i] and arr2[i] != '':
            score -= 1
    return score if score > 0 else 0
  


NOTATION = {True: 4, False: -1}

def check_exam(ref, ans):
    return max(0, sum( NOTATION[r==a] for r,a in zip(ref,ans) if a) )

def check_exam(arr1,arr2):
    k=0; #a place in memory where we shall store the points
    for x in range(len(arr1)): #lets check every answer in the array
        if arr2[x]!='': #and if the answer is not empty
            if arr1[x]==arr2[x]: k+=4 #we will give +4 point for the correct answer
            else: k-=1 #and -1 for any other (incorect) answers
    if k<1: return 0 #if we have 0 ot negative points we should return just zero
    #so we dont embarice further the poor students
    return k

def check_exam(answers, solutions):
    return max( sum( [0, -1, 4][(ans == sol) + (sol != '')] for ans, sol in zip(answers, solutions) ) , 0)

def check_exam(arr1, arr2):
    score = 0

    for i in range(0, len(arr1)):
        if arr1[i] == arr2[i]:
            score = score + 4
        elif arr2[i] != "":
            score -= 1
    return max(score, 0)

  
  


def check_exam(arr1,arr2):
    x = sum([4 if arr1[i] == arr2[i] else 0 if arr2[i] == '' else -1 for i in range(len(arr1))])
    return 0 if x < 0 else x


def check_exam(arr1,arr2):
    
    total = 0
    
    for x,y in zip(arr1, arr2):
        
        if y == '':
            continue
        elif x == y:
            total += 4
        else:
            total -= 1
            
    return total if total>0 else 0


def check_exam(arr1,arr2):
    score = 0
    for n, a in enumerate(arr2):
        if a != '':
            if a == arr1[n]:
                score += 4
            else:
                score -= 1
    return max(score, 0)


def check_exam(arr1,arr2):
    score = 0
    while True:
        for i in range(len(arr2)):
            if arr1[i] == arr2[i]:
                score += 4
            elif arr2[i] == "":
                score += 0
            else:
                score -= 1
        if score < 0:
            return 0
        return score

        
        
  


def check_anwser(actual, expected):
    if not actual:
        return 0
    return 4 if actual == expected else -1

def check_exam(arr1,arr2):
    return max(0, sum(map(check_anwser, arr2, arr1)))



def check_exam(arr1,arr2):
    point=0
    for e in list(zip(arr1,arr2)):point+=4 if e[0]==e[1] else(0 if e[1]==''else -1)
    return 0 if point<0 else point
        
  


def check_exam(arr1,arr2):
    a=sum(4 if x==y else -1 if y else 0 for x,y in zip(arr1,arr2))
    return a if a>0 else 0

def check_exam(arr1,arr2):
    points = 0
    for i in range(len(arr1)):
        points += 4 if arr1[i] == arr2[i] else 0 if arr2[i] == '' else -1
    return points if points > 0 else 0
  


def check_exam(arr1,arr2):
    score = 0
    for i in range(0,len(arr1)):
        if not arr2[i]: continue
        if arr1[i] == arr2[i]: score += 4
        elif arr1[i] != arr2[i]: score -= 1
    if score < 0: score = 0
    return score

def check_exam(arr1,arr2):
    ans = sum([4 if ca==sa else 0 if sa=='' else -1 for ca, sa in zip(arr1, arr2)])
    return ans if ans > 0 else 0

def check_exam(arr1,arr2):
    return max(sum([0 if arr2[i] == '' else 4 if arr1[i] == arr2[i] else -1 for i in range(0, len(arr1))]), 0)

def check_exam(*arr):
    return max(0, sum([-1, 4][a==b] if b else 0 for a,b in zip(*arr)))

def check_exam(arr1,arr2):
    return max(0,sum([4 if arr2[i]==x else 0 if arr2[i]=='' else -1 for (i,x) in enumerate(arr1)]))
  


def check_exam(arr1,arr2):
    score = sum(4 if a == arr1[i] else 0 if not a else -1 for i, a in enumerate(arr2))
    return 0 if score < 0 else score
  


def check_exam(arr1,arr2):
    result = []
    for i in range(len(arr1)):
            if arr2[i] == "":
                result.append(0)
            elif arr1[i]==arr2[i]:
                result.append(4)
            else:
                result.append(-1)
            
    return sum(result) if sum(result)>0 else 0
  


def check_exam(arr1,arr2):
    score = 0
    for elt1, elt2 in zip(arr1, arr2) :
        if not elt2 :
            pass
        elif elt1 == elt2 :
            score += 4
        else :
            score -=1
    return max(score, 0)
        
  


def check_exam(arr1,arr2):
    score=0
    for i,j in zip(arr1,arr2):
        if i==j:
            score+=4
        
        if j=="" and i!="":
            score+=0
        if i!="" and j!="" and i!=j:
            score-=1
    if score<0:
        return 0
    else:
        return score
  


def check_exam(a1, a2):
    return max(0, sum(4 if i == j else -1 for i, j in zip(a1, a2) if j))

def check_exam(arr1,arr2):
    return max(0, sum((arr1[i]==arr2[i])*5-1 for i in range(len(arr1)) if arr2[i] != ''))
  


def check_exam(arr1,arr2):
    return max(0, sum(4 if a1 == a2 else -1 for a1, a2 in zip(arr1, arr2) if a2))
  


def check_exam(a,b):
    res = sum(map(lambda x:0 if x[1] == '' else 4 if x[0] == x[1] else -1  ,zip(a,b)))
    return 0 if res<0 else res

def check_exam(arr1,arr2):
    a = sum([4 if arr1[x] == arr2[x] else -1 if arr2[x] is not '' else 0 for x in range(len(arr1))])
    return a if a >= 0 else 0
  


def check_exam(arr1,arr2):
    return max(sum((-1,4)[a==b] for a,b in zip(arr1,arr2) if b),0)
  


def check_exam(arr1,arr2):
    return max(0, sum([4 if x == y else -1 if y else 0 for x, y in zip(arr1, arr2)]))

def check_exam(arr1,arr2):
    return max(sum(4 if arr1[i] == arr2[i] else -1 if arr2[i] else 0 for i in range(len(arr1))), 0)
    
  


def check_exam(a,b):
    return max(0, sum((a[i]==b[i])*5-1 for i in range(len(a)) if b[i]))

def check_exam(arr1,arr2):
    return max(0, sum((arr1[i]==arr2[i])*5-1 for i in range(len(arr1)) if arr2[i]))

def check_exam(a,b):
    return max(0,sum([4,-1,0][(x!=y)+(y=='')]for x,y in zip(a,b)))

check_exam=lambda e,a:max(0,sum(4*(x==y)or-1for x,y in zip(e,a)if y))

def check_exam(correc,copie):
    return max(0, sum((not not reponse)*(5*(reponse==vrai)-1) for vrai,reponse in zip(correc,copie)))
  




def check_exam(arr1, arr2):

    q = 0
    for i,j in zip(arr1,arr2):
        if i == j:
            q += 4
        elif i != j and j != '':
            q -= 1
    if q > 0:
        return q
    else:
        return 0


from typing import List

def check_exam(arr1: List[str], arr2: List[str]) -> int:
    """ Get the score of the exam based on correct answers and student's answers. """
    _exam_points_sum = sum([0 if not _it[1] else 4 if _it[0] == _it[1] else -1 for _it in zip(arr1, arr2)])
    return _exam_points_sum if _exam_points_sum > 0 else 0

def check_exam(arr1,arr2):
    total_grade = 0
    for i in range(max(len(arr1),len(arr2))):
        if arr2[i] == arr1[i]:
            total_grade += 4
        elif arr2[i] == "":
            total_grade += 0
        elif arr2[i] != arr1[i]:
            total_grade -= 1
    
    return max(total_grade,0)
  


def check_exam(arr1,arr2):
    score = 0
    for i in range(len(arr1)):
        if arr1[i] == arr2[i]:
            score += 4
        elif arr2[i] == '':
            score = score
        elif arr1[i] != arr2[i]:
            score -= 1
    if score < 0:
        return 0
    else:
        return score


def check_exam(arr1,arr2):
    if check0(arr1, arr2)+check1(arr1, arr2)+check2(arr1, arr2)+check3(arr1, arr2)+minus(arr1, arr2)<0:
        return 0
    else:
        return check0(arr1, arr2)+check1(arr1, arr2)+check2(arr1, arr2)+check3(arr1, arr2)+minus(arr1, arr2)
        
def minus(arr1, arr2):
    arr0=[i for i in arr2 if len(i)==0]
    return 0*len(arr0)

def check0(arr1, arr2):
    if arr1[0]==arr2[0]:
        return +4
    else:
        if len(arr2[0])==0:
            return 0
        else:
            return -1
        
def check1(arr1, arr2):
    if arr1[1]==arr2[1]:
        return +4
    else:
        if len(arr2[1])==0:
            return 0
        else:
            return -1
        
def check2(arr1, arr2):
    if arr1[2]==arr2[2]:
        return +4
    else:
        if len(arr2[2])==0:
            return 0
        else:
            return -1
    
def check3(arr1, arr2):
    if arr1[3]==arr2[3]:
        return +4
    else:
        if len(arr2[3])==0:
            return 0
        else:
            return -1

def check_exam(arr1,arr2):
    sum=0
    i=0
    while(i<len(arr1)):
        if(arr1[i]==arr2[i]):
            sum=sum+4
            i=i+1
            continue
        elif(arr2[i]==""):
            sum=sum
            i=i+1
            continue
        else:
            sum=sum-1
            i=i+1
    if(sum<0):
        sum=0
        return sum
    else:
        return sum


def check_exam(arr1,arr2):
    points = 0
    for a,b in zip(arr1, arr2):
        if a==b:
            points += 4
        elif b and 1!=b:
            points -= 1
    return points if points > 0 else 0
  


def check_exam(arr1,arr2):
    score = 0
    for i in range(len(arr1)): 
        if arr2[i] == '':
            continue
        elif arr2[i] != arr1[i]: 
            score -= 1
        else: 
            score += 4
            
    return max(score,0)
  


def check_exam(arr1,arr2):
    score = 0
    for s in range (0, len(arr1)):
        for a in range (0, len(arr2)):
            if s == a :
                if arr1[s] == arr2[a]:
                    score += 4
                elif arr2[a] == "":
                    score += 0
                elif arr1[s] != arr2[a] :
                    score -= 1 
    if score < 0:
         return 0
    else:
         return score
  


def check_exam(arr1='',arr2=''):
    x=0
    for i in range(0,len(arr2),1):
        if arr1[i]==arr2[i]:
            x=x+4
        elif (arr2[i]!=arr1[i]) and (arr2[i]!=''):
            x=x-1
        else:
            x=x
    if x<=0:
        return 0
    else:
        return x
            
  


def check_exam(arr1,arr2):
    result = 0
    for i in range(len(arr1)):
        if arr1[i] == arr2[i]:
            result += 4
        elif arr2[i] == '':
            result += 0
        else:
            result -= 1
    if result > 0:
        return result
    else:
        return 0
  


def check_exam(arr1,arr2):
    score = 0
    for i in range(4):
        if arr1[i] == arr2[i]:
            score = score + 4
        elif arr2[i] == "":
            score = score
        else:
            score = score - 1
    if score < 0:
        score = 0
    return score
  


def check_exam(arr1,arr2):
    return max(0, sum([4 if arr1[i] == arr2[i] else 0 if arr2[i] == "" else -1 for i in range(len(arr1))]))


def check_exam(arr1,arr2):
    n = len(arr1)
    score = 0
    while n > 0:
        n -= 1
        if arr2[n] == "":
            score = score
        elif arr2[n] == arr1[n]:
            score += 4
        else: score -= 1
    return max(score,0)

def check_exam(arr1,arr2):
    exam_score = 0
    for index in range(0,len(arr1)):
        if arr1[index] == arr2[index]:
            exam_score += 4
        elif arr1[index] != arr2[index]:
            if arr2[index] == "":
                exam_score += 0
            else:
                exam_score -=1
    if exam_score < 0:
        return 0
    else:
        return exam_score
                
  


def check_exam(answer_sheet,test):
    score = 0
    for correct, answer in zip(answer_sheet, test):
        if not answer:
            continue
        score += 4 if correct == answer else -1
    return max(0, score)

def check_exam(arr1: list, arr2: list) -> int:
    """ 
    This function returns the score for this array of answers, 
    giving +4 for each correct answer,
    -1 for each incorrect answer, and +0 for each blank answer.
    """
    count = 0
    for i in range(len(arr2)):
        if arr2[i] == arr1[i]:
            count += 4
        elif arr2[i] != arr1[i] and not len(arr2[i]) == 0:
            count -= 1
    return count if count > 0 else 0


def check_exam(arr1,arr2):
    sum = 0
    for a,b in zip(arr1, arr2):
        if a==b:
            sum+=4
        elif b == '':
            sum+=0
        else:
            sum-=1
    if sum<0:
        return 0
    else:
        return sum
    
                
                
  


def check_exam(arr1,arr2):
    finalmark=0
    for i in range(len(arr1)):
        if arr1[i] == arr2[i]:
            finalmark+=4
        if arr1[i] != arr2[i] and arr2[i] != '':
            finalmark-=1
    if finalmark < 0:
        finalmark=0
    return finalmark
  


def check_exam(arr1,arr2):
    ret = 0
    for pair in zip(arr1, arr2):
        if pair[1] == "": continue
        ret += 4 if pair[0] == pair[1] else -1
    return max(0, ret)

def check_exam(arr1,arr2):
    score=0
    for i in range(0,len(arr1)):
        if(arr1[i] == arr2[i]):
            score=score+4
        elif(arr2[i]==""):
            score=score
        else:
            score=score-1
    if score<0:
        return 0 
    return score
  


def check_exam(arr1, arr2):
    result = []
    for a, b in zip(arr1, arr2):
        if a == b:
            result.append(4)
        elif len(a) != len(b):
            result.append(0)
        elif a != b:
            result.append(-1)
    
    score = sum(result)
    if score < 0:
        return 0
    else:
        return score
    


def check_exam(arr1,arr2):
    total = 0
    for x, y in zip(arr1, arr2):
        if x == y: total += 4
        elif y:    total -= 1
    return total if total > 0 else 0
  


def check_exam(arr1,arr2):
    print(arr1)
    print(arr2)
    total = 0
#     for x in range(len(arr1)):
#         if arr1[x] == arr2[x]:  total += 4
#         elif arr2[x] != '':     total -= 1
#     return 0 if total < 0 else total
    
    for i in range(len(arr1)):
        if arr1[i] == arr2[i]:
            total += 4
        elif arr2[i] == "":
            total += 0
        elif arr1[i] != arr2[i] and arr2[i] != "":
            total -= 1 
    return total if total > 0 else 0
        
        
        
  


def check_exam(arr1,arr2):
    mark = 0
    for a1, a2 in zip(arr1, arr2):
        if a1 == a2:
            mark += 4
        elif a1 != a2 and a2 != '':
            mark -=1
    return 0 if mark < 0 else mark


def check_exam(arr1,arr2):
    def grade(a, b):
        if not b:
            return 0
        if a == b:
            return 4
        if a != b:
            return -1
    s = sum(map(lambda x,y:grade(x,y), arr1, arr2))
    return s if s>0 else 0
  


def check_exam(arr1,arr2):
    score = 0
    for i in range (0, int(len(arr2))):
        if arr2[i]:
            if arr1[i] == arr2[i]:
                score +=4
            if arr1[i] != arr2[i]:
                    score -=1
    
    if score >=0:
        return score
    else:
        return 0
  


def check_exam(arr1,arr2):
    score = 0
    for i in range(0, 4):
        if arr1[i] == arr2[i]:
            score += 4
        elif arr2[i] == "":
            score += 0
        else:
            score -= 1
    if score > 0:    
            return score 
    else:
        return 0


def check_exam(a1, a2):
    s = 0
    for x, z in zip(a1, a2):
        if not z:
            pass
        elif x == z: s += 4
        else: s -= 1
    return s if s >= 0 else 0

def check_exam(arr1,arr2):
    result = 0
    for i in range(len(arr1)):
        if arr2[i] == '':
            result += 0
        elif arr1[i] == arr2[i]:
            result += 4
        elif arr1[i] != arr2[i]:
            result -= 1
    return 0 if result < 0 else result
  


def check_exam(arr1,arr2):
    score = 0
    
    for i in range(len(arr2)):
        
        if arr2[i] == arr1[i]:
            score += 4
        elif (arr2[i] != arr1[i]):
            if arr2[i] == '':
                score += 0
            else:
                score -= 1
    if score < 0:
        return 0
    else:
        return score
            
  


def check_exam(arr1,arr2):
    iterator = 0
    score = 0
    while iterator < 4:
        if arr1[iterator] == arr2[iterator]:
            score = score + 4
            iterator = iterator + 1
        elif arr1[iterator] != arr2[iterator] and arr2[iterator] != "":
            score = score - 1
            iterator = iterator + 1 
        else:
            iterator = iterator + 1
    if score < 0:
        score = 0
    return score
        
    
    
        
  


def check_exam(arr1,arr2):
    score = 0
    for c, s in zip(arr1, arr2):
        if s == "":
            score += 0
        elif s == c:
            score += 4
        else:
            score -= 1
    return score if score > 0 else 0

def check_exam(arr1,arr2):
    score = 0
    for i in range(len(arr1)):
        if arr2[i] == '':
            continue
        if arr1[i] == arr2[i]:
            score += 4
        else:
            score += -1
    return score if score > -1 else 0
  


def check_exam(arr1,arr2):
    score =0
    for x in range(len(arr2)):
        if arr1[x] ==arr2[x]:
            score+=4
        elif arr2[x]=="":
            pass
        else:
            score-=1
    
    if score <0:
        return 0
    return score
  


def check_exam(arr1, arr2):
    return max(0, sum(4 if arr1[i] == arr2[i] else -1 for i in range(len(arr1)) if arr2[i]))
  


def check_exam(arr1,arr2):
    
    sum = 0
    for i, j in zip(arr1, arr2):
        if j == '':
            sum += 0
        elif i == j:
            sum += 4
        else:
            sum += -1
    
    if sum < 0:
        return 0
    else:
        return sum
        


def check_exam(arr1,arr2):
    c = 0
    for i in range(len(arr1)):
        if arr1[i] == arr2[i]:
            c += 4
        elif arr2[i] == '':
            c += 0
        else:
            c -= 1
    if c < 0:
        return 0
    else:
        return c

def check_exam(arr1,arr2):
    point = 0
    for x,y in zip(arr1,arr2):
        if x != y:
            if y != "":
                point -= 1
            else:
                point = point + 0
        elif x == y:
            point += 4         
    if point < 0:
        return 0
    else:
        return point


def check_exam(arr1,arr2):
    i = 0
    result = 0
    while i < len(arr1):
        if arr1[i] == arr2[i]:
            result = result + 4
        elif arr2[i] == "":
            result = result + 0
        else:
            result = result - 1
        i = i + 1
    if result < 0:
        return 0
    else:
        return result

def check_exam(arr1,arr2):
    corr = 0
    blank = 0
    for n in range(4):
        if arr2[n] == arr1[n] and arr2[n] != "":
            corr += 1
        elif arr2[n] == "":
            blank += 1
    return (4*corr - (4-corr-blank)) if (4*corr - (4-corr-blank)) > 0 else 0
  


def check_exam(arr1,arr2):
    marks_count = 0
    for i in range(0, len(arr2)):
        if arr2[i] == "":
            marks_count += 0
        elif arr2[i] == arr1[i]:
            marks_count += 4
        elif arr2[i] != arr1[i]:
            marks_count -= 1
        
    
    if marks_count < 0:
        return 0
    else:
        return marks_count
  


def check_exam(arr1,arr2):
    score = 0
    for key, ans in zip(arr1, arr2):
        if key == ans:
            score += 4
        elif ans != "" and ans != key:
            score -= 1
    return score if score > 0 else 0
  


def check_exam(arr1,arr2):
    score = 0
    for x in range(len(arr1)):
        if arr1[x] == arr2[x]:
            score += 4
        elif arr2[x] != "" and arr2[x] != arr1[x]:
            score -= 1
    if score < 0:
        score = 0
    return score

def check_exam(arr1,arr2):
    sum = 0
    for grade in range(len(arr1)):
        if  arr1[grade] == arr2[grade]:
            sum += 4
        elif arr2[grade] == "":
            sum += 0
        else:
            sum -= 1
    return sum if sum > 0 else 0
  


def check_exam(arr1,arr2):
    grade = 0
    
    counter = len(arr1)
    
    scores = 0
    
    while scores < counter:
        if arr1[scores] == arr2[scores]:
            grade = grade + 4
        elif arr1[scores] == "" or arr2[scores] == "":
            grade = grade + 0
        else:
            grade = grade - 1
        
        scores+=1
    
    if grade < 0:
        return 0
    else:
        return grade
            
    
  


def check_exam(arr1,arr2):
    grade = 0
    for answer in range(len(arr1)):
        if arr1[answer] == arr2[answer]:
            grade += 4
        elif arr2[answer] == '':
            grade += 0
        else:
            grade -= 1
    return 0 if grade < 0 else grade

import numpy

def check_exam(arr1,arr2):
    result = 0
    for i in range(len(arr2)):
        if arr1[i] == arr2[i]:
            result += 4
        else:
            result -= 1
    result += arr2.count("")
    return 0 if result < 0 else result
  


def check_exam(arr1,arr2):
    score = 0
    for i in range(len(arr1)): # To cycle through the array.
        if arr2[i] == "": # Blank answer
            score += 0
        elif arr2[i] == arr1[i]: # Correct answer
            score += 4
        else: # Wrong answer
            score -= 1
    
    if score < 0: # To deal with negative scores.
        return 0
    else:
        return score
            
  


def check_exam(arr1,arr2):
    score = 0
    for i in range(len(arr1)):
        if arr1[i] != arr2[i]:
            if arr2[i] != "":
                score-=1
        else:
            score+=4
    return score if score>0 else 0
  


def check_exam(arr1,arr2):
    count = 0
    for i in range(len(arr1)):
        if arr2[i] == "":
            count += 0
        elif arr1[i]==arr2[i]:
            count += 4
        elif arr1[i]!=arr2[i]:
            count -= 1
    return 0 if count<0 else count
  


def check_exam(arr1,arr2):
    liste = []
#enumerate bezieht sich auf Position und Wert in einer Liste   
    for i, x in enumerate (arr1):
        y = arr2 [i]
        if (x != y) :
            if (y == ("")):
                liste.append(0)                
            else :
                liste.append(-1)
        else :
            liste.append(4)
        
    #print (liste)    
    x = sum(liste)
    if x < 0:
        return (0)
    else:
        return(x) 
  


def check_exam(arr1,arr2):
    liste = []
    for i, x in enumerate(arr1) : #weil sich enumerate immer auf Position und WErt (i, x) bezieht
        y = arr2[i]
        if ((x)!=(y)) :
            if y == ("") :
                liste.append(0)
            else : 
                liste.append(-1)
        else : 
            liste.append(4)
    #return(x)
    
        
        
        
        
    
    
    

    x = sum(liste)
    if x <0 : 
        return(0)
    else : 
        return(x)

def check_exam(arr1,arr2):
    score = 0
    for i,j in zip(arr1,arr2):
        if j == "":
            continue
        elif i == j:
            score += 4
        elif i != j:
            score -= 1
        else:
            pass
    if score <= 0:
        return 0
    else:
        return score
    pass
  


def check_exam(arr1,arr2):
    score = 0
    for i in range(len(arr1)):
        validAnswer = arr1[i]
        studentAnswer = arr2[i]
        if studentAnswer == '':
            continue
            
        if studentAnswer == validAnswer:
            score += 4
        else:
            score -= 1
    if score < 0:
        return 0
    else:
        return score
    pass
    
  


def check_exam(arr1,arr2):
    if len(arr1) == len(arr2) and arr1 != [] and arr2 != []:
        score = 0
        for a in range(len(arr1)):
            if arr2[a] == '':
                continue
            elif arr1[a] == arr2[a]:
                score += 4
            else:
                score -= 1
        if score < 0:
            score = 0
    
    return score


def check_exam(arr1,arr2):
    #checking if arr2[i] is blank since otherwise it would say it is different and deduct points
    score = 0
    for i in range(len(arr2)):
        if arr1[i] == arr2[i]:
            score = score + 4
        elif arr2[i] == "":
            score = score + 0
        elif arr1[i] != arr2[i]:
            score = score -1
    
    
    if score < 0:
        return 0
    else:
        return score
  


def check_exam(arr1,arr2):
    
    if len(arr1) != len(arr2):
        return 0
    
    score = 0
    
    for i in range(len(arr1)):
        if arr2[i] == "":
            continue
        
        if arr1[i] == arr2[i]:
            score += 4
            continue
    
        if arr1[i] != arr2[i]:
            score -= 1
            continue
    
    return max(score, 0)
  


def check_exam(arr1,arr2):
    points = 0    
    for n in range(len(arr1)):
        if arr2[n] != '':
            if arr1[n] == arr2[n]:
               points = points + 4
            else:
                points = points - 1
    if points < 0:
        points = 0
    return points


def check_exam(arr1,arr2):
    print((arr1, arr2))
    i = 0
    result = []
    while i < len(arr1):
        if arr1[i] == arr2[i]:
            result.append(4)
        elif arr2[i] == "":
            result.append(0)
        else:
            result.append(-1)
        i += 1
    return sum(result) if sum(result) > 0 else 0
  


def check_exam(arr1,arr2):
    score0 = 0
    score1 = 0
    score2 = 0
    score3 = 0
    if arr1[0] == arr2[0]:
        score0 = 4
    elif arr2[0]=="":
        score0 = 0
    elif arr1[0] != arr2[0]: 
        score0 = -1
    
    if arr1[1] == arr2[1]:
        score1 = 4
    elif arr2[1]=="":
        score1 = 0
    elif arr1[1] != arr2[1]: 
        score1 = -1
    
    if arr1[2] == arr2[2]:
        score2 = 4
    elif arr2[2]=="":
        score2 = 0
    elif arr1[2] != arr2[2]: 
        score2 = -1
        
    if arr1[3] == arr2[3]:
        score3 = 4
    elif arr2[3]=="":
        score3 = 0
    elif arr1[3] != arr2[3]: 
        score3 = -1
        
    totalscore = score0+score1+score2+score3
    
    if totalscore < 0:
        return 0
    else:
        return totalscore