Program to find duplicate elements and delete last occurrence of them in Python

Suppose we have a list of numbers A, we have to find all duplicate numbers and remove their last occurrences.

So, if the input is like [10, 30, 40, 10, 30, 50], then the output will be [10, 30, 40, 50]

To solve this, we will follow these steps −

• seen:= a new map
• d:= a new map
• for i in range 0 to size of nums, do
  • if nums[i] is not in d, then
    • d[nums[i]]:= 1
  • otherwise,
    • d[nums[i]] := d[nums[i]] + 1
• i:= 0
• while i < size of nums, do
  • n:= d[nums[i]]
  • if nums[i] is not in seen, then
    • seen[nums[i]]:= 1
  • otherwise,
    • seen[nums[i]] := seen[nums[i]] + 1
  • if n is same as seen[nums[i]] and n > 1, then
    • delete ith element from nums
    • i := i - 1
  • i := i + 1
• return nums

Let us see the following implementation to get better understanding −

Example

 Live Demo

class Solution:
   def solve(self, nums):
      seen={}
      d={}
      for i in range(len(nums)):
         if not nums[i] in d:
            d[nums[i]]=1
         else:
            d[nums[i]]+=1
      i=0
      while i < len(nums):
         n=d[nums[i]]
         if not nums[i] in seen:
            seen[nums[i]]=1
         else:
            seen[nums[i]]+=1
         if n == seen[nums[i]] and n > 1:
            nums.pop(i)
         i-=1
         i+=1
      return nums
ob = Solution()
print(ob.solve([10, 30, 40, 10, 30, 50]))

Input

[10, 30, 40, 10, 30, 50]

Output

[10, 30, 40, 50]

Arnab Chakraborty

Updated on: 07-Oct-2020

262 Views

Kickstart Your Career

Get certified by completing the course

Get Started