Geek Land has a population of N people and each person's ability to rule the town is measured by a numeric value arr[i]. The two people that can together rule Geek Land must be compatible with each other i.e., the sum of digits of their ability arr[i] must be equal. Their combined ability should be maximum amongst all the possible pairs of people. Find the combined ability of the Ruling Pair.
Example 1:
Input:
N = 5
arr[] = {55, 23, 32, 46, 88}
Output:
101
Explanation:
All possible pairs that are
compatible with each other are- (23, 32)
with digit sum 5 and (55, 46) with digit
sum 10. Out of these the maximum combined
ability pair is (55, 46) i.e. 55 + 46 = 101
Example 2:
Input:
N = 4
arr[] = {18, 19, 23, 15}
Output:
-1
Explanation:
No two people are compatible with each other.
Your Task:
You don't need to read input or print anything. Complete the function RulingPair​() which takes the array arr[] and size of array N as input parameters and returns the answer. If No two people are compatible with
each other then return -1.
Expected Time Complexity: O(N)
Expected Auxiliary Space: O(N)
Constraints:
1 ≤ N ≤ 10^{5}
1 ≤ arr[i] ≤ 10^{9}

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