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/*
Challenge 115
TASK #2 - Largest Multiple
Submitted by: Mohammad S Anwar
You are given a list of positive integers (0-9), single digit.
Write a script to find the largest multiple of 2 that can be formed from the
list.
Examples
Input: @N = (1, 0, 2, 6)
Output: 6210
Input: @N = (1, 4, 2, 8)
Output: 8412
Input: @N = (4, 1, 7, 6)
Output: 7614
*/
#include <algorithm>
#include <iostream>
#include <vector>
using namespace std;
int reverse_cmp(const void* a, const void* b) {
return -(*(int*)a - *(int*)b);
}
int largest_even(vector<int>& nums) {
// smallest even number is last digit
int last_digit = 10;
for (size_t i = 0; i < nums.size(); i++) {
if ((nums[i] % 2) == 0 && nums[i] < last_digit)
last_digit = nums[i];
}
if (last_digit == 10) return 0;
// remove last_digit from list
nums.erase(remove(nums.begin(), nums.end(), last_digit), nums.end());
// sort remaining digits in descending order
sort(nums.begin(), nums.end(), std::greater<>());
int result = 0;
for (size_t i = 0; i < nums.size(); i++)
result = result * 10 + nums[i];
result = result * 10 + last_digit;
return result;
}
int main(int argc, char* argv[]) {
if (argc < 2) return EXIT_FAILURE;
vector<int>nums;
for (int i = 1; i < argc; i++)
nums.push_back(atoi(argv[i]));
cout << largest_even(nums) << endl;
}
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