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