Find the Sum of Encrypted Integers (LeetCode)

Problem Description

Problem Statement	Solution Link	LeetCode Profile
Find the Sum of Encrypted Integers	Find the Sum of Encrypted Integers Solution on LeetCode	vaishu_1904

Problem Description

You are given an integer array nums containing positive integers. We define a function encrypt such that encrypt(x) replaces every digit in x with the largest digit in x. For example, encrypt(523) = 555 and encrypt(213) = 333.

Return the sum of encrypted elements.

Example 1

• Input: nums = [1,2,3]
• Output: 6
• Explanation: The encrypted elements are [1,2,3]. The sum of encrypted elements is 1 + 2 + 3 = 6.

Example 2

• Input: nums = [10,21,31]
• Output: 66
• Explanation: The encrypted elements are [11,22,33]. The sum of encrypted elements is 11 + 22 + 33 = 66.

Constraints

• 1 <= nums.length <= 50
• 1 <= nums[i] <= 1000

Approach

To solve this problem, follow these steps:

1. Define the encrypt function that takes an integer x and returns an integer where every digit of x is replaced by the largest digit in x.
2. For each integer in nums, apply the encrypt function.
3. Calculate the sum of all encrypted integers.
4. Return the sum.

Solution Code

Python

class Solution:
    def findTheSumOfEncryptedIntegers(self, nums: List[int]) -> int:
        def encrypt(x: int) -> int:
            max_digit = max(str(x))
            return int(max_digit * len(str(x)))
        
        return sum(encrypt(num) for num in nums)

C++

#include <vector>
#include <string>
#include <algorithm>
using namespace std;

class Solution {
public:
    int findTheSumOfEncryptedIntegers(vector<int>& nums) {
        auto encrypt = [](int x) {
            string s = to_string(x);
            char max_digit = *max_element(s.begin(), s.end());
            return stoi(string(s.size(), max_digit));
        };
        
        int sum = 0;
        for (int num : nums) {
            sum += encrypt(num);
        }
        return sum;
    }
};

Java

class Solution {
    public int findTheSumOfEncryptedIntegers(int[] nums) {
        int sum = 0;
        for (int num : nums) {
            sum += encrypt(num);
        }
        return sum;
    }
    
    private int encrypt(int x) {
        char[] digits = Integer.toString(x).toCharArray();
        char maxDigit = '0';
        for (char digit : digits) {
            if (digit > maxDigit) {
                maxDigit = digit;
            }
        }
        return Integer.parseInt(new String(new char[digits.length]).replace('\0', maxDigit));
    }
}

Conclusion

The solutions provided demonstrate how to encrypt each integer by replacing its digits with the largest digit found in the integer, and then summing these encrypted integers. This approach ensures the problem is solved efficiently across different programming languages.