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42 lines
848 B
C++

#include <bitset>
#include <cstdio>
#include <iostream>
#include <set>
#include <string>
constexpr long Y = 2000000;
int main()
{
std::bitset<8000000> xs;
long px, py, bx, by;
do {
std::string line;
std::getline(std::cin, line);
if (std::cin.eof())
break;
sscanf(line.c_str(),
"Sensor at x=%ld, y=%ld: closest beacon is at x=%ld, y=%ld",
&px, &py, &bx, &by);
long dist = std::abs(px - bx) + std::abs(py - by);
if (Y < py - dist || Y > py + dist)
continue;
px += 1000000;
long spr = dist - std::abs(py - Y);
for (long j = 0; j <= spr; ++j) {
xs.set(px + j);
xs.set(px - j);
}
} while (1);
std::cout << "Part 1: " << xs.count() - 1 << std::endl;
return 0;
}