Missed arithmetic period - clear my code

Question

I just tried a little online programming quiz that asked me to solve this problem as quickly as possible. I got the correct answer, but I know this is ugly. I'm trying to become a better programmer and write cleaner, more efficient code, so please give me some tips. I have included a description below. PS I think this algorithm fails for the case N = 3

# Enter your code here. Read input from STDIN. Print output to STDOUT
import sys
N= int(sys.stdin.readline())
stringdata =  sys.stdin.readline()
array = stringdata.split(' ')
diff1=[0]*(N-1)
diff2 = [0]*(N-2)
index = 0
diff = 0
for i in  range(0,len(array)-1):
    first_diff[i] = int(array[i+1])-int(array[i])
for i in   range(0,len(diff1)-1):
    second_diff[i] = first_diff[i+1]-first_diff[i]
    if second_diff[i] == 0:
        diff = first_diff[i]
    else:
        index = i
print(int(array[index])+diff)

Task: find the missing term in arithmetic progression.

, . . : , . , . .

N, , . N . , AP ( , ).

, .

5 1 3 5 9 11

7

Answer 1

, . -, . , raw_input ( input Python 3), map int.

n = int(raw_input("Number of Numbers: "))
s = raw_input("List of Numbers, space-separated: ")
nums = map(int, s.split())
assert n == len(nums) and n > 2

: , ( , ) : , . (, ). max, , (d2, index), .

diffs = [(nums[i+1] - nums[i], i) for i in range(n-1)]
(d2, index) = max(diffs)
print nums[index] + d2 / 2

, , :

• (, # read input)
• map int , , , .
• diff1 (aka first_diff),
• diff2; if diff1[i+1] - diff1[i] == 0:
• : range(0,len(array)-1) range(N-1)

Answer 2

1) N ( 5)

2) ( 2)

3) +, - (: 11 5 2 -1 -4)

int diff[]= new int[length-1];
for(int i = 0; i<length-1;i++){
    diff[i] = n1[i+1]-n1[i];
    //System.out.println(diff[i]);
    if(i!=0){
        if(diff[i]<diff[i-1]){
            if(diff[i]<0)
                System.out.println(n1[i]+diff[i-1]);
            else
                System.out.println(n1[i-1]+diff[i]);
            break;
        }
        if(diff[i]>diff[i-1]){
            if(diff[i]<0)
                System.out.println(n1[i-1]+diff[i]);
            else
                System.out.println(n1[i]+diff[i-1]);
            break;
        }
    }
}

n1 - String.

- , .

, , , ,

Answer 3

, , , 8 , .

import re
N = int(raw_input())        #Number of Terms
I = raw_input()             #The Series of Numbers received as a String

I =  re.findall(r'\d+',I)   #Extract items from the string 

I = [int(s) for s in I]     #I is a list with Series of Integers

for x in range(N-1):

    if (I[x]+2 != I[x+1]):
    print I[x]+2

Answer 4

int a[]={1,3,5,7,11};
int i=0,n=5,fd,sd;
printf("output:\n");
do
{
    fd=0;sd=0;
    fd=a[i+1]-a[i];
    sd=a[i+2]-a[i+1];
    if(fd<sd)
    {
        printf("missing term is %d",fd+a[i+1]);
    }
    else if(fd>sd){
       printf("missing term is %d",a[i]+sd);}
    else{
       i++;}
}while((fd==sd)&&i<n-2);

Answer 5

N = input()
max_num = range(N)
s = raw_input()
AP = map(int,s.split())
comm_dif = AP[1]-AP[0]
length = len(AP)
for i in range(N):
    if i != length-1:
        if AP[i+1]-AP[i] != comm_dif:
            print AP[i]+comm_dif

INPUT:

 5
 1 21 31 51 61

:

 41

Answer 6

, , ...

def find_arith(aplist):
   idiff=[]
   flag=0
   for j in range(0, len(aplist)-1):
      diff1 = aplist[j+1] - aplist[j]
      if diff1 < 0:
         flag=1
      idiff.append(abs(diff1))
   if flag==1:
     final_diff=-1*min(idiff)
   else:
     final_diff=min(idiff)
   print(idiff)
   print("final diff:", final_diff)
   for i in range(aplist[0],aplist[len(aplist)-1]+1,final_diff):
      if i not in aplist:
         print(i)

if __name__ == "__main__":

   print("First Result")
   find_arith([13,21,25,33,37,45])
   print("Second Result")
   find_arith([-10,-6,-4,-2])
   print("3rd Result")
   find_arith([-5, -1, 3, 11])
   print("4th Result")
   find_arith([1, 5, 13, 17, 21])

   print("5th Result")
   find_arith([-2, -8, -11, -14, -17, -20, -23, -29])

Answer 7

2 , !! !!

, O (N) , item index 1, , 1, , .

( ) , SYSOUT .

:

 public static int findMissingNumberInAP(int[] ipArr)
{
    // ipArr will always be more than 3 elements in size.
    int maxDiff = ipArr[1] - ipArr[0];
    int i=0;
    while(i<ipArr.length-1)
    {
        if((ipArr[i+1] - ipArr[i]) > maxDiff)
        break;
        i++;
    }
    // This means the 2nd element or i=1 was missing so add ip[0] to
    // any random difference you are good to go.
    if(i == ipArr.length - 1) 
    System.out.println(ipArr[0] + (ipArr[ipArr.length-1]-ipArr[ipArr.length-2]));
    else System.out.println(ipArr[i] + maxDiff);
    // Else just add the maxDiff you got from first step to the position 
    // of i you broke the loop at.
    return -1;
}