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advent-of-code/2022/puzzle-06-01.cc
2022-12-06 10:51:17 +00:00

31 lines
694 B
C++

//
// Created by Matthew Gretton-Dann on 05/12/2021.
//
#include <bitset>
#include <iostream>
#include <string>
#include <vector>
using UInt = std::uint64_t;
auto main() -> int
{
std::string line;
unsigned const match_len{4};
while (std::getline(std::cin, line) && !line.empty()) {
std::bitset<UCHAR_MAX> bits;
for (UInt i{0}; i != line.size(); ++i) {
bits.flip(static_cast<unsigned char>(line[i]));
if (i >= match_len) {
bits.flip(static_cast<unsigned char>(line[i - match_len]));
}
if (i >= (match_len - 1) && bits.count() == match_len) {
std::cout << "First match at " << i + 1 << '\n';
break;
}
}
}
return 0;
}