# Largest Unique Number in Python

PythonServer Side ProgrammingProgramming

Suppose we have a list of numbers, we have to return the number whose occurrence is 1, if no such element is present, then return -1. So if the list is like [5,2,3,6,5,2,9,6,3], then the output will be 9.

To solve this, we will follow these steps −

• We will check each element, and put the elements inside the map, so if the element is not in map, then put a new entry, otherwise increase the value

• then go through the map, when the value is 1, return the key.

## Example(Python)

Let us see the following implementation to get a better understanding −

Live Demo

class Solution(object):
def largestUniqueNumber(self, A):
d = {}
ans = -1
for i in A:
if i not in d:
d[i]=1
else:
d[i] +=1
for a,b in d.items():
if b == 1:
ans = max(a,ans)
return ans
ob1 = Solution()
print(ob1.largestUniqueNumber([5,2,3,6,5,2,9,6,3]))

## Input

[5,2,3,6,5,2,9,6,3]

## Output

9
Published on 27-Feb-2020 07:12:12