September 24Easy

Smallest index with digit sum equal to index

Array
Math

Problem

You are given an integer array nums.

Return the smallest index i such that the sum of the digits of nums[i] is equal to i.

If no such index exists, return -1.

Solution

def get_sum(n):
    res = 0
    while n > 0:
        res += n%10
        n //= 10
    return res

class Solution:
    def smallestIndex(self, nums: List[int]) -> int:
        for i in range(len(nums)):
            if i == get_sum(nums[i]):
                return i
        return -1