44 lines
943 B
C++
44 lines
943 B
C++
|
#include <fstream>
|
||
|
|
#include <iostream>
|
||
|
|
#include <string>
|
||
|
|
#include <vector>
|
||
|
|
|
||
|
|
int find2(std::vector<int> &numbers)
|
||
|
|
{
|
||
|
|
for(auto i = 0; i < numbers.size(); ++i)
|
||
|
|
for(auto j = i + 1; j < numbers.size(); ++j)
|
||
|
|
if(numbers[i] + numbers[j] == 2020)
|
||
|
|
return numbers[i] * numbers[j];
|
||
|
|
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
int find3(std::vector<int> &numbers)
|
||
|
|
{
|
||
|
|
for(auto i = 0; i < numbers.size(); ++i)
|
||
|
|
for(auto j = i + 1; j < numbers.size(); ++j)
|
||
|
|
for(auto k = i + 1; k < numbers.size(); ++k)
|
||
|
|
if(numbers[i] + numbers[j] + numbers[k] == 2020)
|
||
|
|
return numbers[i] * numbers[j] * numbers[k];
|
||
|
|
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
int main()
|
||
|
|
{
|
||
|
|
std::ifstream ifs("data");
|
||
|
|
if(!ifs.is_open())
|
||
|
|
{
|
||
|
|
std::cerr << "Couldn't open file." << std::endl;
|
||
|
|
return -1;
|
||
|
|
}
|
||
|
|
|
||
|
|
std::vector<int> numbers;
|
||
|
|
for(std::string line; std::getline(ifs, line); )
|
||
|
|
numbers.push_back(std::atoi(line.c_str()));
|
||
|
|
|
||
|
|
std::cout << find2(numbers) << std::endl;
|
||
|
|
std::cout << find3(numbers) << std::endl;
|
||
|
|
|
||
|
|
return 0;
|
||
|
|
}
|