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AoC2021 Problem 7
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#include <fstream> | |
#include <string> | |
#include <sstream> | |
#include <iostream> | |
#include <vector> | |
#include <numeric> | |
using namespace std; | |
template <typename T> | |
vector<T> line2vec(string line, char sep = ',') | |
{ | |
vector<T> arr; | |
stringstream ss(line); | |
for (T i; ss >> i;) | |
{ | |
arr.push_back(i); | |
while (ss.peek() == sep) | |
ss.ignore(); | |
} | |
return arr; | |
} | |
int main(int argc, char *argv[]) | |
{ | |
std::ifstream fin; | |
string line; | |
vector<int> crabs; | |
long totalEnergy = 0; | |
std::function<int(int)> arithSum = [=](int dist) -> float | |
{ return dist * (dist + 1) / 2; }; | |
// Read the input and populate the population | |
fin.open(argv[1], std::ios_base::in); | |
getline(fin, line); | |
crabs = line2vec<int>(line, ','); | |
// Find the median value | |
sort(crabs.begin(), crabs.end()); | |
int n = crabs.size(); | |
double moveTo = (double)(crabs[(n - 1) / 2] + crabs[n / 2]) / 2.0; | |
// Part 1 | |
for (int c : crabs) | |
{ | |
totalEnergy += abs(moveTo - c); | |
} | |
cout << "Total Energy: " << totalEnergy << endl; | |
// Part 2 | |
moveTo = std::accumulate(crabs.begin(), crabs.end(), decltype(crabs)::value_type(0)); | |
moveTo /= double(crabs.size()); | |
int moveToDisc_ceil = static_cast<int>(ceil(moveTo)); | |
int moveToDisc_floor = static_cast<int>(floor(moveTo)); | |
int totalEnergy_up = 0; | |
int totalEnergy_down = 0; | |
for (int c : crabs) | |
{ | |
totalEnergy_up += arithSum(abs(moveToDisc_ceil - c)); | |
totalEnergy_down += arithSum(abs(moveToDisc_floor - c)); | |
} | |
totalEnergy = min(totalEnergy_up, totalEnergy_down); | |
cout | |
<< "Part2: " << totalEnergy << endl; | |
return 0; | |
} |
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