diff --git a/HackerRank-A Very Big Sum/A_Very_Big_Sum.py b/HackerRank-A Very Big Sum/A_Very_Big_Sum.py
index bc7e073..9f5ed0f 100644
--- a/HackerRank-A Very Big Sum/A_Very_Big_Sum.py	
+++ b/HackerRank-A Very Big Sum/A_Very_Big_Sum.py	
@@ -5,12 +5,10 @@
 import random
 import re
 import sys
+
 # Complete the aVeryBigSum function below.
 def aVeryBigSum(ar):
-    sum = 0
-    for i in range(len(ar)):
-        sum+=ar[i]
-    return sum
+    return sum(ar)
 
 if __name__ == '__main__':
     fptr = open(os.environ['OUTPUT_PATH'], 'w')
diff --git a/HackerRank-Apple and Orange/Apple_and_Orange.py b/HackerRank-Apple and Orange/Apple_and_Orange.py
index f5bad10..4c89c02 100644
--- a/HackerRank-Apple and Orange/Apple_and_Orange.py	
+++ b/HackerRank-Apple and Orange/Apple_and_Orange.py	
@@ -8,20 +8,8 @@
 
 # Complete the countApplesAndOranges function below.
 def countApplesAndOranges(s, t, a, b, apples, oranges):
-    acount = 0
-    bcount = 0
-    for i in range(len(apples)):
-        temp = a+apples[i]
-        if(temp in range(s,t+1)):
-            acount+=1
-    for i in range(len(oranges)):
-        temp = b+oranges[i]
-        if(temp in range(s,t+1)):
-            bcount+=1
-    print (acount)
-    print (bcount)
-        
-    
+    print(len([a+i for i in apples if a+i >= s and a+i <= t ]))
+    print(len([b+i for i in oranges if b+i >= s and b+i <= t]))
 
 if __name__ == '__main__':
     st = input().split()
diff --git a/HackerRank-Diagonal Difference/Diagonal_Difference.py b/HackerRank-Diagonal Difference/Diagonal_Difference.py
index 7cfabd2..b29761d 100644
--- a/HackerRank-Diagonal Difference/Diagonal_Difference.py	
+++ b/HackerRank-Diagonal Difference/Diagonal_Difference.py	
@@ -6,21 +6,20 @@
 import re
 import sys
 
-# Complete the diagonalDifference function below.
+#
+# Complete the 'diagonalDifference' function below.
+#
+# The function is expected to return an INTEGER.
+# The function accepts 2D_INTEGER_ARRAY arr as parameter.
+#
+
 def diagonalDifference(arr):
-    prim =0
-    sec=0
-    length = len(arr[0])
-    for count in range(length):
-        prim += arr[count][count]
-        sec += arr[count][(length-count-1)]
-    return abs(prim-sec)
-    
+    return abs(sum([arr[i][i] for i in range(len(arr))])-sum([arr[i][len(arr)-i-1] for i in range(len(arr))]))
 
 if __name__ == '__main__':
     fptr = open(os.environ['OUTPUT_PATH'], 'w')
 
-    n = int(input())
+    n = int(input().strip())
 
     arr = []
 
diff --git a/HackerRank-Extra Long Factorials/Extra_Long_Factorials.py b/HackerRank-Extra Long Factorials/Extra_Long_Factorials.py
index 8bd1b70..fed06d9 100644
--- a/HackerRank-Extra Long Factorials/Extra_Long_Factorials.py	
+++ b/HackerRank-Extra Long Factorials/Extra_Long_Factorials.py	
@@ -8,13 +8,9 @@
 
 # Complete the extraLongFactorials function below.
 def extraLongFactorials(n):
-    ans=1
-    while(n!=1):
-        ans*=n
-        n-=1
-    print (ans)
+    if n == 1:
+        return 1
+    return n * extraLongFactorials(n-1)
 
 if __name__ == '__main__':
-    n = int(input())
-
-    extraLongFactorials(n)
+    print(extraLongFactorials(int(input())))
diff --git a/HackerRank-Mini-Max Sum/Mini-Max_Sum.py b/HackerRank-Mini-Max Sum/Mini-Max_Sum.py
index b4ea822..48d4233 100644
--- a/HackerRank-Mini-Max Sum/Mini-Max_Sum.py	
+++ b/HackerRank-Mini-Max Sum/Mini-Max_Sum.py	
@@ -8,12 +8,8 @@
 
 # Complete the miniMaxSum function below.
 def miniMaxSum(arr):
-    sum=0
-    for i in range(len(arr)):
-        sum+=arr[i]
-    print ( sum-max(arr), sum-min(arr))
-
+    s=sum(arr)
+    print(s-max(arr),s-min(arr))
 if __name__ == '__main__':
     arr = list(map(int, input().rstrip().split()))
-
     miniMaxSum(arr)
diff --git a/HackkerRank-Angry Professor/Angry_Professor.py b/HackkerRank-Angry Professor/Angry_Professor.py
index a5a27a8..ee5ad9e 100644
--- a/HackkerRank-Angry Professor/Angry_Professor.py	
+++ b/HackkerRank-Angry Professor/Angry_Professor.py	
@@ -8,14 +8,7 @@
 
 # Complete the angryProfessor function below.
 def angryProfessor(k, a):
-    count=0
-    for i in range(len(a)):
-        if(a[i]<=0):
-            count+=1
-    if(count>=k):
-        return "NO"
-    return "YES"
-
+    return "NO" if len(list(filter(lambda x:x<=0, a)))>=k else "YES" 
 if __name__ == '__main__':
     fptr = open(os.environ['OUTPUT_PATH'], 'w')