Reverse Integer InterviewBit Solution

Problem: Reverse integer

Problem Description:

Reverse digits of an integer.

Example1:

x = 123,
 return 321

Example2:

x = -123,
 return -321

Return 0 if the result overflows and does not fit in a 32 bit signed integer

The approach is to extract the last digit of the number and push it to another number at the unit place.

For example, N = 123
 Take R = 0 // To store reverse number.
 
 Iteration 1:
  Last_Digit = N % 10 = 3
  N = N / 10 = 12
  R = (R * 10) + Last_Digit = 0 + 3 = 3
 
 Iteration 2:
  Last_Digit = N % 10 = 2
  N = N / 10 = 1
  R = (R * 10) + Last_Digit = 30 + 2 = 32
 
 Iteration 3:
  Last_Digit = N % 10 = 1
  N = N / 10 = 0
  R = (R * 10) + Last_Digit = 320 + 1 = 321
 
 Iteration 4:
  N == 0; STOP;

Time Complexity: O(N), N is the number of digits

Space Complexity: O(1)

Code in C++